Psychologic stress and disease activity in patients with inflammatory bowel disease: A multicenter cross-sectional study.

BACKGROUND AND AIMS: Psychologic stress can affect the pathogenesis of inflammatory bowel disease (IBD), but the precise contribution of psychologic stress to IBD remains unclear. We investigated the association of psychologic stress with disease activity in patients with IBD, especially in terms of mental state and sleep condition.
METHODS: This was a multi-center observational study comprising 20 institutions. Data were collected using survey forms for doctors and questionnaires for patients, and the association of psychologic stress with clinical parameters was investigated. Mental state was evaluated using the Center for Epidemiologic Studies Depression (CES-D) scale, and sleep condition was evaluated by querying patients about the severity of insomnia symptoms.
RESULTS: A total of 1078 IBD patients were enrolled, including 303 patients with Crohn's disease and 775 patients with ulcerative colitis. Seventy-five percent of IBD patients believed that psychologic stress triggered an exacerbation of their disease (PSTE group) and 25% did not (non-PSTE group). The CES-D scores were significantly higher for patients with clinically active disease than for those in remission in the PSTE group (median (interquartile range) = 7 (4-9.5) vs. 5 (3-7), p < .0001), but not in the non-PSTE group (5 (2-8) vs. 4 (3-7), p = 0.78). Female sex and disease exacerbation by factors other than psychologic stress were independent factors of psychologic stress-triggered disease exacerbation. Also, patients with insomnia had higher disease activity than those without insomnia, especially in the PSTE group.
CONCLUSIONS: A worsened mental state correlates with disease activity in IBD patients, especially those who believe that their disease is exacerbated by psychologic stress.

Introduction

Inflammatory bowel disease (IBD), comprising Crohn’s disease (CD) and ulcerative colitis (UC), is a refractory disease with repeated remission and exacerbation of symptoms. The etiology of IBD is unknown, but multiple factors may be associated with its pathogenesis. Several reports indicate that environmental factors, such as smoking, diet, infections, sleep, stress, and medication, affect the disease course by interacting with genetic susceptibility and impaired immune system responses. [1, 2] The sum of these environmental factors during the lifetime, termed the “exposome”, appears to be associated with the pathogenesis of IBD. [3] Other environmental factors, such as psychologic stress and sleep condition, may also be associated with the IBD disease course: IBD patients are significantly more depressive than healthy controls, [4] and psychologic stress is associated with an exacerbation of IBD symptoms. [5] Several studies report impaired sleep quality in IBD patients [6-9] and the association of impaired sleep quality with an increased risk of relapse in patients in remission. [8, 10] In contrast, other reports demonstrated no association between psychologic stress and disease exacerbation, [11-14] and the precise etiology of insomnia in patients with IBD is not established. To date, mental status in patients with IBD has not been well assessed, which may account for the contradictory results. Moreover, some environmental factors, such as diet [15] and smoking [16], are known to affect disease activity in patients with IBD, but no studies have focused on psychologic stress and disease activity. In the present study, we aimed to clarify the association between psychologic stress and disease activity in a multicenter large cohort of IBD patients by analyzing their responses to detailed questionnaires about psychologic stress.

Patients and methods

Patients

This was a multicenter cross-sectional observational study conducted by the Osaka Gut Forum comprising 20 institutions in Japan. From November 2013 to August 2014, a total of 1078 IBD patients were enrolled in the present study, including 303 CD patients and 775 UC patients. All patients were Japanese and data were collected from survey forms provided to doctors and questionnaires provided to patients. The patient characteristics are shown in Table 1, and the number of patients included for each analysis in this study is shown in Fig 1. The study protocol was approved by the ethics committee of Osaka University Hospital, the ethics committee of National Hospital Organization Osaka National Hospital, the ethics committee of Kinshukai Infusion Clinic, the ethics committee of Osaka Rosai Hospital, the ethics committee of NTT-West Osaka Hospital, the ethics committee of Sumitomo Hospital, the ethics committee of Toyonaka Municipal Hospital, the ethics committee of Otemae Hospital, the ethics committee of Sakai City Medical Center, the ethics committee of Itami City Hospital, the ethics committee of Nishinomiya Municipal Central Hospital, the ethics committee of Hyogo Prefectural Nishinomiya Hospital, the ethics committee of Osaka Police Hospital, the ethics committee of Yao Municipal Hospital, the ethics committee of National Hospital Organization Osaka-minami National Hospital, and the ethics committee of Higashiosaka City Medical Center. The written informed consent was waived by the ethics committees by giving the participants the opportunity to opt out.

Table 1

Patient characteristics.

	CD n = 303	UC n = 775
Age at enrollment, years, median (IQR)	42 (32–50)	48 (38–62)
Age at onset, years, median (IQR)	24 (19–33)	36 (24–50)
Sex, n, female/male	84/219	371/402
Family history, n, yes/no	14/283	51/710
Smoking, n, non/past or present	195/104	543/214
Montreal A, n, A1/A2/A3	26/231/35	34/424/295
Montreal L, n, L1/L2/L3	96/45/157	―
Montreal B, n, B1/B2/B3	92/110/63	―
Proctitis/Left-sided colitis/Pancolitis, n	―	187/226/343
Perianal lesion, n, yes/no	114/183	7 /759
Extraintestinal manifestation, n, yes/no	27/272	39/698
Colitic cancer, n, yes/no	5/297	7/765
Surgery for IBD, n, yes/no	153/137	22/674
Disease activity, median (IQR)	80.6 (34.7–139) (CDAI)	1 (0–2) (partial Mayo score)
CES-D score, median (IQR)	6 (3–8)	5 (3–7)
Sleeping pill use, n, yes/no	25/272	37/725
Psychotropic drug use, n, yes/no	8/279	14/748

Fig 1

Study flow chart.

Medical records

The survey form queried the patients’ background, including sex, disease duration, blood type, family history, smoking status, age at disease onset, surgical history for IBD, perianal disease, and extra-intestinal manifestations, and disease-specific items such as disease location and disease activity. Age at onset was categorized according to the Montreal classification [17] into two groups: A1/A2 (40 years old or younger) and A3 (over 40 years old). Disease location was also categorized according to the Montreal classification. [17]

Patient questionnaire

Patients filled out the questionnaire regarding potential factors of disease exacerbation. We asked “What factor do you think is the cause of disease exacerbation? Please choose all of the alternatives that apply to you. (multiple answers allowed)”, and patients selected from the following alternatives, “seasonality”, “problem with work or family”, “psychologic stress”, “infections”, “other than above”, and “not sure” (S1 Fig). In addition to this information, there were questions regarding disease activity, mental state, and sleep condition during the past week.

Evaluation of disease activity

Disease activity in CD patients was evaluated according to the Crohn’s disease activity index (CDAI) [18] and in UC patients according to the partial Mayo score. [19] Patients with a CDAI score of 150 or more and a partial Mayo score of 2 or more were defined as having active disease.

Evaluation of mental state and sleep condition

To evaluate each patient’s mental state, we used an 11-item form of the Center for Epidemiologic Studies Depression (CES-D) scale, Japanese version. [20, 21] The CES-D scale is a validated scale, comprising 9 “negative” items and 2 “positive” items, with each “negative” item scored on a Likert scale from 0 (none of the time) to 2 (all of the time) and each “positive” item scored from 0 (all of the time) to 2 (none of the time) (S1 Table). The total points range from 0 to 22 and a depressive state was defined as a CES-D score of at least 7. [22] To assess the general sleep condition, we used a simple version of a sleep questionnaire based on the validated Insomnia Severity Index (ISI) [23] to reduce recall bias. Patients were asked how much they felt their daily life was affected by their sleep condition during the past week, scored on a Likert scale from 1 (not at all) to 5 (exceedingly). We defined a Likert score of 3 or more as insomnia. [22, 24]

Statistical analysis

Statistical analyses were performed using the Pearson’s chi-square test and Mann-Whitney U test, and multivariate logistic regression analysis was performed with factors associated with disease exacerbation induced by psychologic stress. In logistic regression analysis, the covariates with significant difference in the univariate analysis were selected. To estimate p values for interactions, two-way analysis of variance was used for continuous variables and Cox regression analysis for categorical data. All of the data obtained from this study were analyzed using JMP Pro version 12 and statistical significance was set at a p value less than 0.05.

Results

Seventy-five percent of IBD patients recognize psychologic stress as a factor for disease exacerbation

We first investigated the factors for disease exacerbation in patients with IBD. Of the 1078 IBD patients initially enrolled, 210 were excluded due to incomplete information about exacerbating factors, and therefore a total of 868 patients were included in the analysis of the exacerbation factor (Fig 1). Analysis of all the questionnaires revealed that 75.1% of the IBD patients responded that they believed their disease activity was exacerbated by psychologic stress, and psychologic stress was the most common factor for exacerbation among the alternative responses (Fig 2). When patients were divided into 2 groups–patients who believed that psychologic stress triggered an exacerbation of their disease (PSTE group) and those who did not (non-PSTE group)–the proportions of CD patients and UC patients were 75.0% and 75.2%, respectively. These data indicate that, among both CD and UC patients, 75% of IBD patients believed that psychologic stress exacerbated their disease.

Fig 2

Distribution of exacerbation factors.

Patients filled out questionnaires regarding possible disease exacerbation factors by selecting from alternative responses. Multiple answers were allowed.

Disease activity in IBD patients is exacerbated by an altered mental state

We next analyzed the association between mental state and disease activity in 786 patients (Fig 1). In all IBD patients, the CES-D scores were significantly higher in patients with active disease than for those in remission (S2 Fig). The CES-D scores at the time of the survey were significantly higher for patients with clinically active disease than for those in remission in the PSTE group, but not in the non-PSTE group, with a p value for interaction of 0.066 (Fig 3). We further investigated the correlation between CES-D scores and disease activity using a scatter diagram, which revealed a positive correlation between CES-D scores and disease activity in both CD and UC patients in the PSTE group, but no correlation in the non-PSTE group (S3 Fig). These findings revealed a positive association between CES-D scores and disease activity among IBD patients who believed psychologic stress triggered an exacerbation of their disease.

Fig 3

Association between disease activity and depressive state in IBD patients.

Among patients who responded that they believed that psychologic stress triggered an exacerbation of their disease (PSTE group), the CES-D scores were significantly higher for patients with active disease than for those in remission (median (interquartile range (IQR)) = 7 (4–9.5) vs. 5 (3–7), p < .0001). Among patients who responded that they did not believe psychologic stress exacerbated their disease (non-PSTE group), the CES-D scores did not differ significantly between patients with active disease and patients in remission (median (IQR) = 5 (2–8) vs. 4 (3–7), p = 0.78).

Factors associated with the psychologic stress for disease exacerbation

We analyzed the factors associated with the belief that psychologic stress is involved in disease exacerbation by comparing the patient characteristics between the PSTE and non-PSTE groups. Univariate analysis followed by multivariate analysis revealed that problems with work or family, seasonal disease exacerbation, infections, and diet, along with female sex were independent factors associated with psychologic stress-triggered disease exacerbation (Table 2). These findings suggest that patients who believed that psychologic stress triggered an exacerbation of their disease are predominantly female, and think that problems with work or family exacerbate the disease but other environmental factors do not.

Table 2

Factors associated with psychologic stress-triggered disease exacerbation.

	Univariate analysis			Multivariate analysis
	PSTE group	Non-PSTE group	p value	Odds ratio (95% CI)	p value
Sex (female), n (%)	301 (46.2)	82 (38.0)	0.034	1.52 (1.07–2.18)	0.021
Exacerbation by problems with work or family (yes), n (%)	305 (46.8)	63 (29.2)	< .0001	1.97 (1.38–2.86)	0.0002
Seasonal disease exacerbation (yes), n (%)	305 (53.5)	121 (65.1)	0.0058	0.62 (0.43–0.89)	0.0091
Exacerbation by infections (yes), n (%)	165 (25.3)	83 (38.4)	0.0002	0.54 (0.37–0.77)	0.0009
Exacerbation by diet (yes), n (%)	33 (5.1)	37 (17.1)	< .0001	0.26 (0.15–0.45)	< .0001

Insomnia is associated with active disease in IBD

We investigated the association between sleep condition and disease activity. A total of 1000 patients were included after excluding 78 patients due to incomplete answers regarding their insomnia symptoms (Fig 1). The proportion of total IBD patients with insomnia was 22.3%, with no significant difference between CD (25.7%) and UC (21.0%) patients. We also investigated the association between disease activity and sleep condition. The proportion of patients with active disease was significantly greater among patients with insomnia than among those without insomnia (S4 Fig). This difference was also observed in both CD and UC patients.

Insomnia is associated with disease activity especially in patients who believed that psychologic stress triggered their disease exacerbation

Finally, we investigated the association of insomnia and disease activity by analyzing the proportion of patients with insomnia between those with active disease and those in remission in the PSTE and non-PSTE groups. We excluded 188 patients due to incomplete responses regarding exacerbating factors for psychologic stress (Fig 1). In the PSTE group, the proportion of patients with insomnia was significantly higher for patients with active disease than for those in remission. No significant difference was detected in the non-PSTE group, with p value for the interaction of 0.437 (Fig 4). These data indicate that the association between insomnia and disease activity was particularly strong in the PSTE group.

Fig 4

Association between disease activity and insomnia in IBD patients.

In the PSTE group, the proportion of patients with insomnia (insomnia (+)) was significantly higher for patients with active disease than for those in remission (38.8% (76/196) vs. 22.8% (94/413), p < .0001). No significant difference was detected in the non-PSTE group (26.6% (17/64) vs. 18.7% (26/139), p = .2030, respectively).

Discussion

The findings of the present study revealed that 75% of IBD patients considered their disease to be exacerbated by an altered mental state, and among these patients, disease activity correlated positively with CES-D scores, which is widely used as an indicator of the mental state. In addition to a previous report showing an association between psychologic stress and disease activity in IBD patients, [25] the present data provide new insight that a depressive state is associated with disease activity in a subgroup of IBD patients who believe that psychologic stress triggers an exacerbation of their disease. Reports on the association of psychologic status and insomnia with disease activity provide conflicting evidence, which might be due to the lack of patient stratification based on the patients’ belief. Psychologic stress can influence gut inflammation through various mechanisms via the hypothalamus–pituitary–adrenal axis and the autonomic nervous system, resulting in the production of proinflammatory cytokines, activation of macrophages, and alteration of intestinal permeability and gut microbiota. [26-28] Also, psychotherapy by a counselor specially trained in the management of IBD improves the course of IBD in individuals with psychosocial stress, [29] indicating that managing psychologic stress may be a therapeutic target for IBD. Previous reports also show that female sex is associated with anxiety in IBD patients [30] as well as in the general population, [31] which is consistent with our present data that more female patients reported that psychologic stress induced disease exacerbation. Increased psychologic stress in the PSTE group may augment the fear for exacerbation and thereby affect these mechanisms, whereas other factor(s) may affect disease activity in the non-PSTE group. Moreover, we recently reported that seasonality of disease onset and exacerbation was observed especially in young-onset IBD patients. [32] Together, these data suggest that multiple environmental factors are associated with disease activity.

Insomnia was associated with the disease activity of IBD in the present study, consistent with previous studies. [6-8] Changes in the sleep architecture during acute infection correlate with the levels of plasma interleukin (IL)-6, [33] and IL-6 administration significantly decreases slow-wave sleep during the first half of sleep and increases slow-wave sleep during the second half. [34] Moreover, sleep deprivation increases the production of inflammatory cytokines, such as IL-6 and TNF-alpha. [35] In a murine colitis model, sleep deprivation worsened inflammation and delayed recovery. [36] In the present study, we showed that insomnia was associated with disease activity particularly in patients who believed that psychologic stress triggered an exacerbation of their disease. A previous study reported that depressive symptoms were a strong predictor of sleep disturbance, [10] and our present data also suggest that psychologic stress is associated with disease flare in patients with insomnia. The results of effect modification were different between depressive state and insomnia, indicating that psychologic stress-triggered disease exacerbation is strongly connected to the association between depressive state and disease activity, whereas the association between insomnia and disease activity cannot be ruled out, even in patients who do not recognize that psychologic stress triggers an exacerbation of their disease activity. Compared with insomnia, a depressive state might contribute more to increase disease activity in patients recognizing that psychologic stress triggers disease exacerbation, but the present study design does not allow for a direct comparison. To clarify this further, we are conducting a prospective study.

The present study has some limitations. First, because it was a cross-sectional observational study, we could not clarify whether a depressive state and insomnia are causes or consequences of exacerbated symptoms. To address this issue, we are now performing a prospective study to analyze disease activity, and the mental and sleep states at multiple time-points. Second, insomnia was assessed by self-reported questionnaires, not by objective measurements. Objective monitoring of sleep quality in a multicenter study setting, however, is associated with many difficulties, including equipment requirements, high cost, and adequate patient recruitment. Moreover, patient-reported outcomes have recently become an important aspect of assessing activity of IBD to optimize the therapeutic outcome and quality of life. [37, 38] The importance of patient-reported outcomes for assessing the clinical status of IBD, especially for monitoring the influence of environmental factors, should be discussed further.

In conclusion, our data revealed that a worsened mental state correlates with disease activity in IBD patients, especially those who believe that psychologic stress triggers an exacerbation of their disease. Although further studies are necessary to reveal the mechanism of the association between these environmental factors and the disease course, the present findings can be applied to develop tailor-made therapies for IBD patients based on their levels of psychologic stress.

The original version of the questionnaire.

(TIFF)

Click here for additional data file.

In all IBD patients, the CES-D scores were significantly higher for patients with active disease than for those in remission (median (IQR) = 6 (4–9) vs. 5 (3–7), p < .0001).

(TIFF)

Click here for additional data file.

Scatter diagram to evaluate the correlation between the CES-D scores and disease activity among patients with CD (n = 177) and UC (n = 416) in the PSTE group and the non-PSTE group.

In the PSTE group, the CES-D scores correlated positively with disease activity (r = 0.26, p = 0.0004 in CD and r = 0.21, p = 0.0007 in UC). In patients with CD (n = 60) and UC (n = 133) in the non-PSTE group, the CES-D scores did not correlate with disease activity (r = -0.04, p = 0.98 in CD and r = 0.12, p = 0.17 in UC).

(TIFF)

Click here for additional data file.

Comparison of the proportion of patients with active disease in the insomnia (+) or insomnia (-) groups.

Among patients with CD and UC, the proportion of patients with active disease was significantly higher in the insomnia (+) group than in the insomnia (-) group.

(TIFF)

Click here for additional data file.

The CES-D scale.

(TIFF)

Click here for additional data file.

15 Oct 2019

PONE-D-19-26952

Vulnerability to psychologic stress and disease activity in patients with inflammatory bowel disease: A multicenter observational study

PLOS ONE

Dear Dr. Iijima,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Although your manuscript is interesting, the two reviewers addressed several major and minor concerns about your manuscript. Please revise your manuscript carefully.

We would appreciate receiving your revised manuscript by Nov 29 2019 11:59PM. When you are ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter.

To enhance the reproducibility of your results, we recommend that if applicable you deposit your laboratory protocols in protocols.io, where a protocol can be assigned its own identifier (DOI) such that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols

Please include the following items when submitting your revised manuscript:

A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). This letter should be uploaded as separate file and labeled 'Response to Reviewers'.

A marked-up copy of your manuscript that highlights changes made to the original version. This file should be uploaded as separate file and labeled 'Revised Manuscript with Track Changes'.

An unmarked version of your revised paper without tracked changes. This file should be uploaded as separate file and labeled 'Manuscript'.

Please note while forming your response, if your article is accepted, you may have the opportunity to make the peer review history publicly available. The record will include editor decision letters (with reviews) and your responses to reviewer comments. If eligible, we will contact you to opt in or out.

We look forward to receiving your revised manuscript.

Kind regards,

Kenji Hashimoto, PhD

Academic Editor

PLOS ONE

Journal Requirements:

When submitting your revision, we need you to address these additional requirements.

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at http://www.journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and http://www.journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

2. Please provide additional details regarding participant consent. In the ethics statement in the Methods and online submission information, please ensure that you have specified (1) whether consent was informed and (2) what type you obtained (for instance, written or verbal, and if verbal, how it was documented and witnessed). If your study included minors, state whether you obtained consent from parents or guardians. If the need for consent was waived by the ethics committee, please include this information.

3. Please include additional information regarding the questionnaire regarding potential factors of disease exacerbation used in the study and ensure that you have provided sufficient details that others could replicate the analyses. For instance, if you developed this questionnaire as part of this study and it is not under a copyright more restrictive than CC-BY, please include a copy, in both the original language and English, as Supporting Information.

4. Thank you for stating the following in the Acknowledgments Section of your manuscript:

'This work was supported by a Grant-in-Aid from the Japan Society for the Promotion of Science (Grant No.

26460969).'

We note that you have provided funding information that is not currently declared in your Funding Statement. However, funding information should not appear in the Acknowledgments section or other areas of your manuscript. We will only publish funding information present in the Funding Statement section of the online submission form.

Please remove any funding-related text from the manuscript and let us know how you would like to update your Funding Statement. Currently, your Funding Statement reads as follows:

'The authors received no specific funding for this work.'

5. Thank you for stating the following in the Competing Interests section:

'The authors have declared that no competing interests exist.'

We note that one or more of the authors are employed by a commercial company: Kinshukai Infusion clinic

1. Please provide an amended Funding Statement declaring this commercial affiliation, as well as a statement regarding the Role of Funders in your study. If the funding organization did not play a role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript and only provided financial support in the form of authors' salaries and/or research materials, please review your statements relating to the author contributions, and ensure you have specifically and accurately indicated the role(s) that these authors had in your study. You can update author roles in the Author Contributions section of the online submission form.

Please also include the following statement within your amended Funding Statement.

“The funder provided support in the form of salaries for authors [insert relevant initials], but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section.”

If your commercial affiliation did play a role in your study, please state and explain this role within your updated Funding Statement.

2. Please also provide an updated Competing Interests Statement declaring this commercial affiliation along with any other relevant declarations relating to employment, consultancy, patents, products in development, or marketed products, etc.

Within your Competing Interests Statement, please confirm that this commercial affiliation does not alter your adherence to all PLOS ONE policies on sharing data and materials by including the following statement: "This does not alter our adherence to  PLOS ONE policies on sharing data and materials.” (as detailed online in our guide for authors http://journals.plos.org/plosone/s/competing-interests).  If this adherence statement is not accurate and  there are restrictions on sharing of data and/or materials, please state these. Please note that we cannot proceed with consideration of your article until this information has been declared.

Please include both an updated Funding Statement and Competing Interests Statement in your cover letter. We will change the online submission form on your behalf.

Please know it is PLOS ONE policy for corresponding authors to declare, on behalf of all authors, all potential competing interests for the purposes of transparency. PLOS defines a competing interest as anything that interferes with, or could reasonably be perceived as interfering with, the full and objective presentation, peer review, editorial decision-making, or publication of research or non-research articles submitted to one of the journals. Competing interests can be financial or non-financial, professional, or personal. Competing interests can arise in relationship to an organization or another person. Please follow this link to our website for more details on competing interests: http://journals.plos.org/plosone/s/competing-interests

6. Thank you for including your ethics statement: The ethics committees of all participating institutions approved the study protocol.

Please amend your current ethics statement to include the full name of the ethics committee/institutional review board(s) that approved your specific study.

Once you have amended this/these statement(s) in the Methods section of the manuscript, please add the same text to the “Ethics Statement” field of the submission form (via “Edit Submission”).

For additional information about PLOS ONE ethical requirements for human subjects research, please refer to http://journals.plos.org/plosone/s/submission-guidelines#loc-human-subjects-research.

7. Please include captions for your Supporting Information files at the end of your manuscript, and update any in-text citations to match accordingly. Please see our Supporting Information guidelines for more information: http://journals.plos.org/plosone/s/supporting-information.

Additional Editor Comments (if provided):

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Partly

**********

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: The authors conducted an interesting multicenter cross-sectional survey to evaluate the association between psychological factors and disease activity in 1078 patients with inflammatory bowel diseases (IBD). In this study, patients believed that psychological stress was the most common factor for a trigger of their disease exacerbation. The authors also explored the association between CES-D or insomnia and disease activity. In the exploratory analyses, the authors conducted subgroup analyses based on whether patients believe psychological stress is the most important factor for a trigger of their disease exacerbation.

The research question is interesting, and the data shown in this manuscript should be helpful for both healthcare providers and IBD patients to discuss the importance of assessing patients’ psychological condition. However, the manuscript is not straightforward. The authors should simply focus on their main research question in the manuscript. To make the manuscript simple and more reasonable, I have several comments below.

1. The word, “vulnerability to psychological stress” may be improper because the authors did not measure the vulnerability such as lack of stress coping. I assume that “vulnerability to psychological stress” means that patients believed that psychological stress triggered their disease exacerbation in this study. This concept may be better to have a different name such as patients’ belief.

2. Instead of psychological stress, the authors measure depression (CES-D) and insomnia. The concept of psychological stress is different from depression and insomnia. The authors should clearly use the word such as depression and insomnia instead of psychological stress when they discuss depression and insomnia. In other words, the author should only use the word “psychological stress” when they discuss the results of questionnaire regarding factors related to disease exacerbation.

3. I believe that the most important information of this article may be that psychological stress was the most common factor for a trigger of their disease exacerbation. The authors should write the exact sentences to shown how they asked this question and what the choices were.

4. The authors used the word group 1 and group 2 which were based on whether patients answered whether psychological stress triggered their disease exacerbation. The expression of group 1 or group 2 may not be easy to follow for readers because name of group numbers (group 1 and group 2) are confusing. Please rename group1 and group 2 for readers’ understanding.

5. It seems that authors tried to show there is effect modification (i.e. interaction) between group 1 and group 2 regarding the association between CES-D or insomnia and disease activity. In the current analysis, the authors conducted only subgroup analyses based on group 1 and group2. Please show the p-value for interaction. Based on the p-value for interaction, the authors can discuss whether depression or insomnia are associated with disease activity in Group1 but not in Group 2.

6. The authors used CES-D as a continuous variable and showed the significant difference between remission and active patients in Group 1 in Figure 2. It may be better to use categorical variable such as depressive or not based on the cut-off written in the method section. If the authors use CES-D as a continuous variable, please discuss minimal clinically important difference (MCID) of CES-D.

7. Instead of table 1 and table 2, it may be better to show only patient characteristics in all patients, Group 1, and Group 2 in the same table without any statistical testing. In other words, the authors may delete table 1 and table 2, and they create a new table showing the patient characteristics.

8. I believe that the supplementary figure 1 is important because it shows patients’ selection. Please transfer the supplementary figure 1 to figure 1 in the manuscript.

9. There may be too many figures and supplementary figures. Please decrease the number of figures only focus on exacerbation factors and the subgroup analysis of Group 1/2 regarding depression and insomnia because this may be a main research question of this study. If this is not, the authors should show what is their main research question.

10. As shown in the supplementary figure 1, the authors selected the study population in two ways. If the authors decrease the number of figures and analyses, it may be possible to select patients in one process.

11. In the overall analyses, the authors showed only p-values in figures. Please show the point estimates such as mean difference and 95% intervals. This is important to discuss whether the difference is clinically important or not. This issue is related to MCID as I commented in No 6.

12. The authors should carefully interpret results in this study. Because this is the cross-sectional study, it is reasonable to consider the depression or insomnia is due to disease activity rather than vice-versa. Please discuss the results from the viewpoint above. Moreover, the authors should explain how patients’ belief (psychological stress triggered their disease exacerbation) affects the association of depression or insomnia with disease activity. In other word, please explain the mechanism of this effect modification if the authors find the significant interaction (please see the comments No 5).

13. Overall, there may be better words and sentences to show what the authors want to discuss in this manuscript. Please ask English editing to native and academic English editors.

1. It is better to show the study design in detail in the title. This is a multicenter cross-sectional survey or multicenter cross-sectional study.

2. In the introduction, the authors do not need to discuss seasonality because this is different from the current study purpose.

3. In the method section, please briefly mention the validity and reliability of CES-D and insomnia questionnaire based on previous questionnaire development study conducted by the developers.

4. In the introduction and discussion, the author should summarize previous studies evaluating patients’ belief of disease exacerbation triggers and discuss the discrepancy between the results of current study and those of previous studies with possible reasons.

5. In the introduction and discussion, the author should summarize previous studies evaluating depression or insomnia and disease activity, and please discuss the discrepancy between the results of current study and those of previous studies with possible reasons.

Reviewer #2: This cross sectional study assessed psychological stress and insomnia in approximately 1,000 IBD subjects. The main findings were that most patients believed that stress is associated with disease activity and, in patients who believe this, that insomnia was also associated with disease activity. The data are well presented and my main concern is with the discussion surrounding the data. It has been known for many years that most patients believe that disease activity not only results stress, anxiety and depression, but that the converse is also true (that stress, anxiety and depression results in subsequent disease activity) and the findings from this paper are not novel in any way. The authors mention in the discussion that they are performing a prospective study and this would be a much more interesting study, allowing them to determine causative associations rather than just associations. Indeed, Gracie et al. (Gastroenterology 2018) have already shown that there is a bi-directional association between psychological disability and disease activity. With regard to insomnia, it is well known that sleep disturbance is intimately associated with psychological disability while it is also known that sleep disturbance is particularly common in those with gastrointestinal disorders. Indeed it would be surprising if disordered sleep patterns were not associated with active disease, merely by the effect of abdominal pain and diarrhoea on sleep.

This does not mean that the study is of no value, but the discussion section should be altered to more accurately reflect the cross-sectional nature of the data. As an example, the statement " .. and the results suggest that psychological stress can be an initiator of disease" (line 281) is simply not appropriate. Similarly, the statement "our present data also suggest that high vulnerability to psychologic stress is associated with disease flare in patients with insomnia" (line 273) is not supported by the data. Finally, their conclusion "In conclusion, our data revealed that psychologic stress and insomnia affect disease activity in IBD patients, especially..." (line 292) is wrong, since it is just as likely that disease activity affects psychological stress and insomnia.

The English, references and figures are appropriate

**********

6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files to be viewed.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email us at figures@plos.org. Please note that Supporting Information files do not need this step.

29 Mar 2020

Response to Reviewer #1:

Thank you very much for reviewing our manuscript. We have revised the manuscript in response to all comments received.

1. The word, “vulnerability to psychological stress” may be improper because the authors did not measure the vulnerability such as lack of stress coping. I assume that “vulnerability to psychological stress” means that patients believed that psychological stress triggered their disease exacerbation in this study. This concept may be better to have a different name such as patients’ belief.

Thank you for this suggestion. As the reviewer pointed out, we intended to investigate patients who believed that psychologic stress triggered an exacerbation of their disease. In the revised manuscript, we changed the title and amended the related sentences explaining the concept of the patients’ belief.

2. Instead of psychological stress, the authors measure depression (CES-D) and insomnia. The concept of psychological stress is different from depression and insomnia. The authors should clearly use the word such as depression and insomnia instead of psychological stress when they discuss depression and insomnia. In other words, the author should only use the word “psychological stress” when they discuss the results of questionnaire regarding factors related to disease exacerbation.

To avoid misunderstanding, we used the phrase “psychologic stress” only when discussing the results of the questionnaire, and used the phrase “depressive state” when referring to the association between CES-D scores and disease activity.

3. I believe that the most important information of this article may be that psychological stress was the most common factor for a trigger of their disease exacerbation. The authors should write the exact sentences to shown how they asked this question and what the choices were.

The exact sentences of the question are now provided on lines 143-147 in the revised manuscript. And according to the suggestion by the Journal Requirements, we have also included the original Japanese version as S1 Fig in Supporting Information.

4. The authors used the word group 1 and group 2 which were based on whether patients answered whether psychological stress triggered their disease exacerbation. The expression of group 1 or group 2 may not be easy to follow for readers because name of group numbers (group 1 and group 2) are confusing. Please rename group1 and group 2 for readers’ understanding.

We renamed group 1 and group 2 as the PSTE (psychologic stress-triggered exacerbation) group and the non-PSTE group. Thank you for this suggestion.

5. It seems that authors tried to show there is effect modification (i.e. interaction) between group 1 and group 2 regarding the association between CES-D or insomnia and disease activity. In the current analysis, the authors conducted only subgroup analyses based on group 1 and group2. Please show the p-value for interaction. Based on the p-value for interaction, the authors can discuss whether depression or insomnia are associated with disease activity in Group1 but not in Group 2.

Figure 2 (new Fig 3), which shows the association between the CES-D scores and disease activity in each group, indicates a tendency toward an interaction with a p-value of 0.066. This result indicates a positive association between CES-D scores and disease activity only in the PSTE group and no association was observed in the non-PSTE group. As for Figure 5 (new Fig 4), which shows the association between the clinical activity scores and insomnia in each group, the p-values for the group interactions were 0.61 for CD and 0.23 for UC, respectively. These data indicate a positive association between insomnia and disease activity, especially in the PSTE group. Although significant differences were not observed in the non-PSTE group, an association between insomnia and disease activity cannot be ruled out. Further studies are needed to clarify this point, and we are now conducting a prospective study. We amended our description of the results in lines 195-196 and 246-249, and added sentences to the Discussion (lines 310-318) in the revised manuscript.

6. The authors used CES-D as a continuous variable and showed the significant difference between remission and active patients in Group 1 in Figure 2. It may be better to use categorical variable such as depressive or not based on the cut-off written in the method section. If the authors use CES-D as a continuous variable, please discuss minimal clinically important difference (MCID) of CES-D.

We re-analyzed the data using categorical variables with Fisher’s exact test, and showed that a higher proportion of active patients were in a depressive state than in a non-depressive state in the PSTE group, but this difference was not observed in the non-PSTE group.

Depressive state Non-depressive state p-value

Active disease, n(%)

PSTE group 97 (42.9) 96 (26.2) .0001

Non-PSTE group 18 (34.0) 41 (29.3) 0.6001

As shown in Supplementary Figure 4 (new S3 Fig), however, the CES-D score correlated significantly with the clinical activity indices in the PSTE group, but not in the non-PSTE group, although both scores were used as continuous variables. Therefore, we would like to present the data as continuous variables. There is no defined MCID for the CES-D score, but, according to the reviewer’s suggestion, we added the median values and interquartile range (IQR) in the figure legend of new Fig 3 (former Figure 2) in the revised manuscript.

7. Instead of table 1 and table 2, it may be better to show only patient characteristics in all patients, Group 1, and Group 2 in the same table without any statistical testing. In other words, the authors may delete table 1 and table 2, and they create a new table showing the patient characteristics.

In response to this comment, we now provide the patient characteristics in the new Supplementary Table 1, which combines the previous Table 1 and 2, and relabeled the previous Supplementary Table 1 as a new Table 1. We understand that showing all the factors in univariate analyses is not always necessary, but we also consider that the multivariate analyses shown in the old Table 1 and 2 are very important data. We therefore revised these tables by showing only the factors for which multivariate analyses were performed (new Table 2 and 3, respectively).

8. I believe that the supplementary figure 1 is important because it shows patients’ selection. Please transfer the supplementary figure 1 to figure 1 in the manuscript.

We modified and moved Supplementary Figure 1 to Fig 1, as suggested by the reviewer in comment No.10.

9. There may be too many figures and supplementary figures. Please decrease the number of figures only focus on exacerbation factors and the subgroup analysis of Group 1/2 regarding depression and insomnia because this may be a main research question of this study. If this is not, the authors should show what is their main research question.

During the review process, we decided that analyses of the detailed insomnia symptoms in the insomnia (+) and insomnia (-) groups did not need to be shown in the present form. We therefore deleted the previous Figure 4, Supplementary Figure 6, and related descriptions in the manuscript were modified. We also deleted previous Supplementary Figures 2 and 5 in which the proportions of patients are shown, and the related descriptions in the manuscript were amended.

10. As shown in the supplementary figure 1, the authors selected the study population in two ways. If the authors decrease the number of figures and analyses, it may be possible to select patients in one process.

As we performed the depression and insomnia analyses similarly, we amended the new Fig 1 (former Supplementary Figure 1) in which the study is shown as one process.

11. In the overall analyses, the authors showed only p-values in figures. Please show the point estimates such as mean difference and 95% intervals. This is important to discuss whether the difference is clinically important or not. This issue is related to MCID as I commented in No 6.

For analyses with continuous variables by which the point estimates can be shown such as in Figure 2 (new Fig 3), Figure 5 (new Fig 4), and Supplementary Figure 3 (new S2 Fig), we show median values with the IQR described in the figure legends. For analyses with categorical variables such as in Figure 3 (new S4 Fig), we show the number and ratio of patients in each group.

12. The authors should carefully interpret results in this study. Because this is the cross-sectional study, it is reasonable to consider the depression or insomnia is due to disease activity rather than vice-versa. Please discuss the results from the viewpoint above. Moreover, the authors should explain how patients’ belief (psychological stress triggered their disease exacerbation) affects the association of depression or insomnia with disease activity. In other word, please explain the mechanism of this effect modification if the authors find the significant interaction (please see the comments No 5).

As described in the limitation section, we understand that this study design does not clarify whether a depressive state or insomnia are a cause or consequence of the exacerbated symptoms, and would like to emphasize that when patients are divided into PSTE and non-PSTE groups, different associations between the disease activity and depressive state/insomnia are observed in each group. The findings of an effect modification differed between depressive state and insomnia, indicating that a patient’s belief in psychologic stress-triggered disease exacerbation is strongly connected to the association between the depressive state and disease activity, although an association between insomnia and disease activity cannot be ruled out. A depressive state might be more strongly involved than insomnia in disease activity in patients recognizing psychologic stress-triggered disease exacerbation, but in the present study design, a direct comparison cannot be performed and a prospective study targeting this issue is needed. Thank you for the important suggestion and we have now added sentences addressing this point in lines 319-327 of the revised manuscript.

13. Overall, there may be better words and sentences to show what the authors want to discuss in this manuscript. Please ask English editing to native and academic English editors.

The manuscript was edited by professional native-English speaking science editors from SciTechEdit International, LLC.

1. It is better to show the study design in detail in the title. This is a multicenter cross-sectional survey or multicenter cross-sectional study.

We changed the title to indicate that this was a multicenter cross-sectional study.

2. In the introduction, the authors do not need to discuss seasonality because this is different from the current study purpose.

We deleted the sentences describing seasonality in the Introduction.

3. In the method section, please briefly mention the validity and reliability of CES-D and insomnia questionnaire based on previous questionnaire development study conducted by the developers.

The CES-D scale was validated by Yokoyama E, et al. (Sleep. 2010. Reference No.21) As for the insomnia questionnaire, we used a simple version of the sleep questionnaire based on the validated Insomnia Severity Index (ISI) (Bastien CH, et al. Sleep Med. 2001, which has been added as Reference No. 23) to reduce recall bias. It is commonly given to patients to assess their present sleep conditions in clinical practice. We briefly described the questionnaire in lines 164-166 of the revised manuscript.

4. In the introduction and discussion, the author should summarize previous studies evaluating patients’ belief of disease exacerbation triggers and discuss the discrepancy between the results of current study and those of previous studies with possible reasons.

Patients’ beliefs about some environmental factors affecting IBD, such as diet (Limdi JK, et al. Inflamm Bowel Dis. 2016, which has been added as Reference No. 15) and smoking (Saadoune N, et al. Eur J Gastroenterol Hepatol. 2015, which has been added as Reference No. 16) have been reported, but no studies have focused on patients’ beliefs regarding psychologic stress and disease activity. The present data provide new insight that a depressive state is one of the factors associated with disease activity in a subgroup of IBD patients who believed that psychologic stress triggered an exacerbation of their disease. We now describe this in lines 91-93 in the Introduction and lines 282-285 in the Discussion of the revised manuscript.

5. In the introduction and discussion, the author should summarize previous studies evaluating depression or insomnia and disease activity, and please discuss the discrepancy between the results of current study and those of previous studies with possible reasons.

As described in the Introduction, there are conflicting reports regarding whether psychologic state and insomnia are associated with disease activity. In the present study, we found that depressive state is a factor associated with disease activity in a subgroup of IBD patients who believed that psychologic stress triggered an exacerbation of their disease. Previous conflicting reports might be due to the lack of patient stratification based on patients’ belief. We now discuss this in lines 285-287 of the revised manuscript.

Response to Reviewer #2:

Thank you very much for reviewing our manuscript. We have revised the manuscript in response to all comments received.

1. the discussion section should be altered to more accurately reflect the cross-sectional nature of the data. As an example, the statement " .. and the results suggest that psychological stress can be an initiator of disease" (line 281) is simply not appropriate. Similarly, the statement "our present data also suggest that high vulnerability to psychologic stress is associated with disease flare in patients with insomnia" (line 273) is not supported by the data.

Thank you for the suggestion. We agree and have deleted these statements to avoid misunderstanding.

2. Finally, their conclusion "In conclusion, our data revealed that psychologic stress and insomnia affect disease activity in IBD patients, especially..." (line 292) is wrong, since it is just as likely that disease activity affects psychological stress and insomnia.

As we described in the limitation section, in the present study, we could not clarify whether psychologic stress and insomnia affect disease activity or vice versa. Therefore, we changed the statement to “worsened mental state correlates with disease activity in IBD patients, especially...” in lines 342-343 of the revised manuscript, and deleted the word “insomnia” because of negative results regarding an effect modification between the PSTE and non-PSTE groups. Thank you for your suggestion.

Response to Journal Requirements:

When submitting your revision, we need you to address these additional requirements.

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at http://www.journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and http://www.journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

We amended the manuscript so as to meet PLOS ONE’s style requirements.

2. Please provide additional details regarding participant consent. In the ethics statement in the Methods and online submission information, please ensure that you have specified (1) whether consent was informed and (2) what type you obtained (for instance, written or verbal, and if verbal, how it was documented and witnessed). If your study included minors, state whether you obtained consent from parents or guardians. If the need for consent was waived by the ethics committee, please include this information.

The written informed consent was waived by the ethics committees by giving the participants the opportunity to opt out. We described this on lines 125-126 of the revised manuscript.

3. Please include additional information regarding the questionnaire regarding potential factors of disease exacerbation used in the study and ensure that you have provided sufficient details that others could replicate the analyses. For instance, if you developed this questionnaire as part of this study and it is not under a copyright more restrictive than CC-BY, please include a copy, in both the original language and English, as Supporting Information.

According to the suggestion by the Reviewer #1, we described the detailed information of the questionnaire in English on the Methods of the revised manuscript. We have also included the original Japanese version as S1 Fig in Supporting Information.

4. Thank you for stating the following in the Acknowledgments Section of your manuscript:

'This work was supported by a Grant-in-Aid from the Japan Society for the Promotion of Science (Grant No. 26460969).'

We note that you have provided funding information that is not currently declared in your Funding Statement. However, funding information should not appear in the Acknowledgments section or other areas of your manuscript. We will only publish funding information present in the Funding Statement section of the online submission form.

Please remove any funding-related text from the manuscript and let us know how you would like to update your Funding Statement. Currently, your Funding Statement reads as follows:

'The authors received no specific funding for this work.'

We have removed the funding-related text from the manuscript and updated the Funding Statement section in the online submission form.

5. Thank you for stating the following in the Competing Interests section:

'The authors have declared that no competing interests exist.'

We note that one or more of the authors are employed by a commercial company: Kinshukai Infusion clinic

Kinshukai Infusion clinic is not a commercial company but a medical corporation. The author has declared that no competing interests exist.

1. Please provide an amended Funding Statement declaring this commercial affiliation, as well as a statement regarding the Role of Funders in your study. If the funding organization did not play a role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript and only provided financial support in the form of authors' salaries and/or research materials, please review your statements relating to the author contributions, and ensure you have specifically and accurately indicated the role(s) that these authors had in your study. You can update author roles in the Author Contributions section of the online submission form.

Please also include the following statement within your amended Funding Statement.

“The funder provided support in the form of salaries for authors [insert relevant initials], but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section.”

If your commercial affiliation did play a role in your study, please state and explain this role within your updated Funding Statement.

This work was supported by a Grant-in-Aid from the Japan Society for the Promotion of Science (Grant No. 26460969). The funder did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. We have now updated the Funding Information of the online submission system and added above statements in lines 359-362 in Author Contributions of the revised manuscript.

2. Please also provide an updated Competing Interests Statement declaring this commercial affiliation along with any other relevant declarations relating to employment, consultancy, patents, products in development, or marketed products, etc.

Within your Competing Interests Statement, please confirm that this commercial affiliation does not alter your adherence to all PLOS ONE policies on sharing data and materials by including the following statement: "This does not alter our adherence to PLOS ONE policies on sharing data and materials.” (as detailed online in our guide for authors http://journals.plos.org/plosone/s/competing-interests). If this adherence statement is not accurate and there are restrictions on sharing of data and/or materials, please state these. Please note that we cannot proceed with consideration of your article until this information has been declared.

Please include both an updated Funding Statement and Competing Interests Statement in your cover letter. We will change the online submission form on your behalf.

Please know it is PLOS ONE policy for corresponding authors to declare, on behalf of all authors, all potential competing interests for the purposes of transparency. PLOS defines a competing interest as anything that interferes with, or could reasonably be perceived as interfering with, the full and objective presentation, peer review, editorial decision-making, or publication of research or non-research articles submitted to one of the journals. Competing interests can be financial or non-financial, professional, or personal. Competing interests can arise in relationship to an organization or another person. Please follow this link to our website for more details on competing interests: http://journals.plos.org/plosone/s/competing-interests

We have read the journal's policy and declare that the authors have no competing interests which can alter our adherence to PLOS ONE policies on sharing data and materials. We have amended the Disclosure Statement on lines 373-374 of the revised manuscript, and the cover letter.

6. Thank you for including your ethics statement: The ethics committees of all participating institutions approved the study protocol.

Please amend your current ethics statement to include the full name of the ethics committee/institutional review board(s) that approved your specific study.

Once you have amended this/these statement(s) in the Methods section of the manuscript, please add the same text to the “Ethics Statement” field of the submission form (via “Edit Submission”).

For additional information about PLOS ONE ethical requirements for human subjects research, please refer to http://journals.plos.org/plosone/s/submission-guidelines#loc-human-subjects-research.

The study protocol was approved by the ethics committee of Osaka University Hospital, the ethics committee of National Hospital Organization Osaka National Hospital, the ethics committee of Kinshukai Infusion Clinic, the ethics committee of Osaka Rosai Hospital, the ethics committee of NTT-West Osaka Hospital, the ethics committee of Sumitomo Hospital, the ethics committee of Toyonaka Municipal Hospital, the ethics committee of Otemae Hospital, the ethics committee of Sakai City Medical Center, the ethics committee of Itami City Hospital, the ethics committee of Nishinomiya Municipal Central Hospital, the ethics committee of Hyogo Prefectural Nishinomiya Hospital, the ethics committee of Osaka Police Hospital, the ethics committee of Yao Municipal Hospital, the ethics committee of National Hospital Organization Osaka-minami National Hospital, and the ethics committee of Higashiosaka City Medical Center. We described this on lines 114-125 of the revised manuscript and added the same text to the “Ethics Statement” field of the submission form.

7. Please include captions for your Supporting Information files at the end of your manuscript, and update any in-text citations to match accordingly. Please see our Supporting Information guidelines for more information: http://journals.plos.org/plosone/s/supporting-information.

We included captions for Supporting Information files at the end of the manuscript, and updated in-text citations.

Submitted filename: Araki Stress Reponse to Reviewers v2.4.pdf

Click here for additional data file.

14 Apr 2020

PONE-D-19-26952R1

Psychologic stress and disease activity in patients with inflammatory bowel disease: A multicenter cross-sectional study

PLOS ONE

Dear Dr. Iijima,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Again the reviewer addressed several major concerns about your revised manuscript. Please revise your manuscript carefully.

We would appreciate receiving your revised manuscript by May 29 2020 11:59PM. When you are ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter.

To enhance the reproducibility of your results, we recommend that if applicable you deposit your laboratory protocols in protocols.io, where a protocol can be assigned its own identifier (DOI) such that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols

Please include the following items when submitting your revised manuscript:

A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). This letter should be uploaded as separate file and labeled 'Response to Reviewers'.

A marked-up copy of your manuscript that highlights changes made to the original version. This file should be uploaded as separate file and labeled 'Revised Manuscript with Track Changes'.

An unmarked version of your revised paper without tracked changes. This file should be uploaded as separate file and labeled 'Manuscript'.

Please note while forming your response, if your article is accepted, you may have the opportunity to make the peer review history publicly available. The record will include editor decision letters (with reviews) and your responses to reviewer comments. If eligible, we will contact you to opt in or out.

We look forward to receiving your revised manuscript.

Kind regards,

Kenji Hashimoto, PhD

Academic Editor

PLOS ONE

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: (No Response)

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Partly

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: No

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: This revision substantially improved the quality of reporting. However, there are several issues which the authors should clarify. Especially, the authors should explain why they believe that there is effect modification between PSTE groups (i.e. biological mechanism).

1. Please report the method to estimate P values for interactions in the Method section.

2. Please explain the possible biological mechanism which causes effect modification (i.e. interaction).

3. The authors answered that there is no defined MCID for CES-D. Please mention the search method for this (i.e. database for searching and search terms). I briefly searched and found one article related to MCID (PMID: 27300327). There should be more articles related to this issue.

4. In the results section of the abstract, please report the details of the results such as proportion, point estimate, and 95% CI.

5. Figure 1 is difficult to follow. Moreover, the numbers written in the Patients section seem different from those in Figure 1. Please check them. If the numbers are correct, please clearly report the study flow. The authors should also report how many patients visited the study sites during the study period and how many were actually recruited.

6. In the statistical analysis section, the description is too simple. Please report the details such as how they selected covariates for the logistic regression model. If the authors want to conduct causal inference, they need to select covariates based on theories instead of statistical covariate selection.

7. In figure 3, the authors compared between remission and active patients with stratification of PSTE. To harmonize the way of showing results to figure 3, figure 4 should also show the comparison between remission and active patients with stratification of PSTE without subgrouping CD/UC.

8. The authors should rethink the reasons to conduct multivariable analyses. They excluded “problems with work or family” from covariates because they thought that this was a potential confounder. If this is a confounder, it is better to adjust it to evaluate the independent association. However, the authors excluded it. Please explain for what purpose they conducted multivariable analyses.

9. In Table 2 and Table 3, it is difficult to understand the results. Please use same method to conduct univariate and multivariable analyses such as logistic regression models. Moreover, the method of covariate selection and purpose of these analyses are unclear.

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files to be viewed.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email us at figures@plos.org. Please note that Supporting Information files do not need this step.

2 May 2020

Response to Reviewer #1:

Thank you very much for reviewing our manuscript. We have now revised the manuscript in response to all comments received.

1. Please report the method to estimate P values for interactions in the Method section.

To estimate P values for interactions, two-way analysis of variance was used for continuous variables and Cox regression analysis for categorical data. We have added the information in the Method section.

2. Please explain the possible biological mechanism which causes effect modification (i.e. interaction).

In the current epidemiological study design, we cannot elucidate the definite biological mechanism underlying the effect modification. Multivariate analysis showed that patients with the PSTE group are predominantly female and do not think that other environmental factors exacerbated disease (Table 2). As described in the Discussion, psychologic stress can influence gut inflammation through various mechanisms via the hypothalamus–pituitary–adrenal axis and the autonomic nervous system, resulting in the production of proinflammatory cytokines, activation of macrophages, and alteration of intestinal permeability and gut microbiota [26-28]. Previous reports also show that female sex is associated with anxiety in IBD patients [30]. Increased psychologic stress in the PSTE group may augment the fear for exacerbation and thereby affect these mechanisms, whereas other factor(s) may affect disease activity in the non-PSTE group. We are currently conducting a basic research to explore the pathophysiological role of psychologic stress for intestinal inflammation. We have added the discussion in the Discussion of the revised manuscript.

3. The authors answered that there is no defined MCID for CES-D. Please mention the search method for this (i.e. database for searching and search terms). I briefly searched and found one article related to MCID (PMID: 27300327). There should be more articles related to this issue.

In the paper presented by the Reviewer, the MCID for 15-item form of CES-D scale was investigated for German patients with depression, which is different from the 11-item CES-D we have used in the present manuscript. We searched papers using PubMed/MEDLINE with the search query of “11-item CES-D”[All Fields] AND “MCID”[All Fields] and no paper was found. We have additionally tried to search papers with the query of "MCID"[All Fields] AND "CES-D"[All Fields], three papers were found. MCID shown in the first paper was what the Reviewer #1 presented, the second was what the authors empirically considered for 20-item CES-D (PMID: 31037211), and third was not for CES-D (PMID: 31562683), so none of them can account for our query. Moreover, previous reports using CES-D score were targeting patients who had already been diagnosed as depression, which is totally different from our target of patients who are not diagnosed as depression in almost all cases. In the present study we would just like to investigate the statistically significant difference in the CES-D scores between the PSTE group and the non-PSTE group, and would not like to observe the decrease in the CES-D score by clinical intervention.

4. In the results section of the abstract, please report the details of the results such as proportion, point estimate, and 95% CI.

We have added the details of the results within the word count limit in the revised abstract.

5. Figure 1 is difficult to follow. Moreover, the numbers written in the Patients section seem different from those in Figure 1. Please check them. If the numbers are correct, please clearly report the study flow. The authors should also report how many patients visited the study sites during the study period and how many were actually recruited.

In the first draft, we displayed the depressive state and insomnia analysis charts separately. In the second submission we revised as the Reviewer #1 instructed us to combine them, which seemed to be harder to follow the study flow. We have now renewed Figure 1 and clarified the study flow in the manuscript. And we actually recruited a total of 1078 cases, and the number of the patients who visited the study sites is unknown in this study design.

6. In the statistical analysis section, the description is too simple. Please report the details such as how they selected covariates for the logistic regression model. If the authors want to conduct causal inference, they need to select covariates based on theories instead of statistical covariate selection.

In logistic regression analysis, the covariates with significant difference in the univariate analysis were selected. We have added the explanation to the Statistical analysis section.

7. In figure 3, the authors compared between remission and active patients with stratification of PSTE. To harmonize the way of showing results to figure 3, figure 4 should also show the comparison between remission and active patients with stratification of PSTE without subgrouping CD/UC.

In Figure 3 the factors related to PSTE are analyzed, while in Figure 4 the factors related to insomnia are analyzed, both of which are classified into the PSTE group and the non-PSTE group. Unlike CES-D, the insomnia score is a binary value, and if CD and UC are to be analyzed without distinction, disease activity must be expressed as a binary value in the active phase and the remission phase because the disease activity scores are different between CD and UC. Therefore, we have amended Figure 4 as the active patient group and the remission patient group were set on the horizontal axis as in Figure 3, and the vertical axis was defined as the proportion of insomnia patients. Analysis by Pearson’s chi-square test showed that, in the PSTE group, the proportion of insomnia patients was significantly higher in active patients than in those in remission, but the difference was not observed in the non-PSTE group. The P value of the interaction was 0.437, and no interaction was observed in both groups. These results are same as the former analysis, but thanks to the Reviewer’s suggestion, we have now clearly showed that insomnia is associated with disease activity especially in patients with the PSTE group.

8. The authors should rethink the reasons to conduct multivariable analyses. They excluded “problems with work or family” from covariates because they thought that this was a potential confounder. If this is a confounder, it is better to adjust it to evaluate the independent association. However, the authors excluded it. Please explain for what purpose they conducted multivariable analyses.

In the first analysis, the alternative “problems with work or family” was excluded from the analysis because it seemed to be strongly related to psychologic stress and the results might be confusing to the readers. When we actually put it in variables, problems with work and family was shown to be an independent factor positively associated with PSTE, and other variables with significant difference in univariate analysis were remained as independent factors. These results indicate that patients in the PSTE group think that problems with work or family exacerbate the disease but other environmental factors do not. We have now amended Table 2.

9. In Table 2 and Table 3, it is difficult to understand the results. Please use same method to conduct univariate and multivariable analyses such as logistic regression models. Moreover, the method of covariate selection and purpose of these analyses are unclear.

Table 2 analyzes factors related to PSTE, and Table 3 analyzes factors related to insomnia. In the first draft of Table 2 and 3, the results of the univariate analysis for all the variables were shown, but we deleted the variables without significant difference in the univariate analysis according to the Reviewer #1’s suggestion. The analysis methods are the same. However, with the change in Figure 4 for the Question No.7, we would like to emphasize psychologic stress rather than insomnia, and have now deleted the Table 3 to avoid confusing.

Submitted filename: Araki Stress Response to Reviewers R2 v3.2.pdf

Click here for additional data file.

5 May 2020

Psychologic stress and disease activity in patients with inflammatory bowel disease: A multicenter cross-sectional study

PONE-D-19-26952R2

Dear Dr. Iijima,

We are pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it complies with all outstanding technical requirements.

Within one week, you will receive an e-mail containing information on the amendments required prior to publication. When all required modifications have been addressed, you will receive a formal acceptance letter and your manuscript will proceed to our production department and be scheduled for publication.

Shortly after the formal acceptance letter is sent, an invoice for payment will follow. To ensure an efficient production and billing process, please log into Editorial Manager at https://www.editorialmanager.com/pone/, click the "Update My Information" link at the top of the page, and update your user information. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org.

If your institution or institutions have a press office, please notify them about your upcoming paper to enable them to help maximize its impact. If they will be preparing press materials for this manuscript, you must inform our press team as soon as possible and no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

With kind regards,

Kenji Hashimoto, PhD

Section Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

14 May 2020

PONE-D-19-26952R2

Psychologic stress and disease activity in patients with inflammatory bowel disease: A multicenter cross-sectional study

Dear Dr. Iijima:

I am pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please notify them about your upcoming paper at this point, to enable them to help maximize its impact. If they will be preparing press materials for this manuscript, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

For any other questions or concerns, please email plosone@plos.org.

Thank you for submitting your work to PLOS ONE.

With kind regards,

PLOS ONE Editorial Office Staff

on behalf of

Prof. Kenji Hashimoto

Section Editor

PLOS ONE