Is it really always only the others who are to blame? GP's view on medical overuse. A questionnaire study.

BACKGROUND: Medical overuse is a common problem in health care. Preventing unnecessary medicine is one of the main tasks of General Practice, so called quaternary prevention. We aimed to capture the current opinion of German General Practitioners (GPs) to medical overuse.
METHODS: A quantitative online study was conducted. The questionnaire was developed based on a qualitative study and literature search. GPs were asked to estimate prevalence of medical overuse as well as to evaluate drivers and solutions of medical overuse. GPs in Bavaria were recruited via email (750 addresses). A descriptive data analysis was performed. Additionally the association between doctors' attitudes and (1) demographic variables and (2) interest in campaigns against medical overuse was assessed.
RESULTS: Response rate was 18%. The mean age was 54 years, 79% were male and 68% have worked as GP longer than 15 years. Around 38% of medical services were considered as medical overuse and nearly half of the GPs (47%) judged medical overuse to be the more important problem than medical underuse. Main drivers were seen in "patients´ expectations" (76%), "lack of a primary care system" (61%) and "defensive medicine" (53%), whereas "disregard of evidence/guidelines" (15%) and "economic pressure on the side of the doctor" (13%) were not weighted as important causes. Demographic variables did not have an important impact on GPs´ response pattern. GPs interested in campaigns like "Choosing Wisely" showed a higher awareness for medical overuse, although these campaigns were only known by 50% of the respondents. DISCUSSION: Medical overuse is an important issue for GPs. Main drivers were searched and found outside their own sphere of responsibility. Campaigns as "Choosing Wisely" seem to have a positive effect on GPs attitude, but knowledge is still limited.

Introduction

Medical overuse is a common problem in health care [1, 2]. Despite frequent discussions in public, politics and the medical community, there is still no consistent concept for defining and measuring medical overuse [3, 4]. Medical overuse is often described as “a health care service [that] is provided under circumstances in which its potential for harm exceeds the possible benefit” [5]. This rather simplified definition only corresponds to obviously ineffective services. However, many services are in a “nebulous grey zone, where evidence is lacking or weak.” [2]. In this grey zone, patients’ and physicians’ attitudes and beliefs might play the ultimate role in determining and tackling with low value care [6].

Much of the current literature pays particular attention to drivers and solutions of medical overuse [see for example 7, 8, 9]. Factors promoting medical overuse in general practice were attributed to internal factors such as physicians’ need for reassurance and the belief that action is better than inaction [10]. Also, cognitive biases in medical decision making and an insufficient ability of dealing with uncertainty seem to play an important role [11, 12]. New medical technology and its general availability are frequently misleading physicians to use it whether appropriate or not [13]. Causes of medical overuse were also attributed to external factors such as patient expectations [14] and fear of litigation resulting in defensive medicine [15].

Estimations of the extent of medical overuse range from 10% to 30% of the total expenditure in the US healthcare system depending on the respective definition and research method [16, 17]. In 2011, between $158 and $226 billion were spent for overtreatment [17-19]. Beside the economic burden, there is an important medical impact. Unnecessary investigation and treatment will frequently result in psychological and physical harm [20].

In light of lowering risk-factor thresholds and disease mongering the prevention of medical overuse–also named quaternary prevention—is getting more and more important [21]. Supporting physicians in this task is the important purpose of campaigns like “Choosing Wisely”[22]. Previous studies have shown that “Choosing Wisely” can have a positive impact on physicians’ attitudes, but are still not known enough by the vast majority of practicing doctors [23, 24].

The GP’s role as a gate-keeper is weakened considerably in the German health care system, where patients have direct access to specialists without the need to be referred. Nevertheless, GPs might be in a central position for preventing medical overuse, considering that it is easier not to initiate a cascade of diagnostic tests and their therapeutic consequences, rather than trying to stop it when it is in the full run [25, 26].

In a previous study, we qualitatively explored perceptions and opinions of medical overuse amongst German GPs [27]. They perceived medical overuse as a common problem in the German health care system, mainly caused by drivers like defensive medicine, lack of a primary care system and patients’ expectations. Solutions proposed were reducing defensive medicine, focusing on shared-decision-making and conducting stepwise diagnostic investigation. In this current study, we wanted to quantify these data. The primary aim was to capture the current opinion of GPs regarding medical overuse. The secondary aim was to assess the association between doctors’ attitudes and (1) demographic variables, and (2) campaigns´ awareness and interest.

Materials and methods

Study design and sample

We conducted an online questionnaire study. The study is reported following the STROBE and CHERRIES statement [28, 29]. The questionnaire was developed following the generalization model described by Mayring [30]. In order to gather general conclusions about a specific topic, the results of a qualitative study can be used to develop a quantitative study.

Referring to the results of the qualitative study by Alber et al [31], we decided to consider the following domains of medical overuse as to be important: perceived relevance, drivers of medical overuse and solutions. In the development of the items, both findings of a literature search [4, 16, 32–38] and experts’ opinion were included. The software SurveyMonkey was used for programming the questionnaire [39].

A pre-test of the questionnaire evaluating its design and content was performed with nine physicians and two medical students. Pre-tests were carried out using the “thinking aloud” method [40]. For the recruiting of participants, the following inclusion criteria were applied: Qualified GPs and GP trainees, specialist doctors in internal medicine or physicians without specialist training working as primary care physicians.

The link to the questionnaire was sent via email together with an invitation to participate. Email addresses were selected from the registry of GPs in the Bavarian Association of Statutory Health Insurance Physicians, short Bavarian ASIP. (The Bavarian ASIP is one of the healthcare system’s self-administration bodies, responsible for ensuring that outpatient medical treatment is provided and for the distribution of payments to physicians in ambulatory care). In the case of missing email addresses in the ASIP registry, addresses were searched via Internet (Google search) resulting in a total of 750 addresses.

An email containing a link to the survey, a description of study’s objective, information on data handling (anonymity), the informed consent statement and the invitation to participate was delivered to GPs in North and East Bavaria on 20 June 2017. A reminder was sent one week later. Data collection was closed 18 days after the first mail.

Ethical approval was granted by the Ethics Committee of the Faculty of Medicine of the Friedrich-Alexander University Erlangen-Nürnberg (91_17 B, 07.04.2017).

Measures

The questionnaire consisted of two parts. Firstly, we collected demographic variables such as gender, age, professional title and experience, area of work and practice volume. Secondly, we asked 36 questions on the following topics in the main section of our questionnaire:

Estimate of the prevalence of medical overuse in health services: “How high would you estimate the percentage of medical overuse in Germany at the moment?” on a scale between 0 and 100%.

Perceived need for action: “Where do you currently see more need for action regarding the quality of treatment for our patients?” Decision has to be made on a visual analogue scale between medical underuse and medical overuse.

Perceived causes for medical overuse: Out of a list of eight suspected causes such as patient expectation, marketing of the pharmaceutical industry, disease mongering, the three most important sources of medical overuse should be selected. There was no ranking option, just a selection mode.

Campaigns’ familiarity and use: selection of “Choosing wisely” [41], “Smarter medicine” [42], “Less is more” [43], “Klug entscheiden” [44], “Quaternary prevention” [25] and “None of the named campaigns”.

B. Personal attitude towards medical overuse

Participants were asked to make a decision on a six-point Likert scale. Endpoints ranged from “I completely disagree” to “I totally agree” (topic five and eight) or from”not correct at all” to “fully correct”(topic six and seven).

Tendency to justify medical overuse: 13 items on medical decision making in everyday practice, e.g., “Patients with acute low back pain seem to be dissatisfied when symptoms are not clarified by imaging techniques.”

Perceived relevance of medical overuse: Six items, e.g., “I know patients being harmed by medical overuse.”

Evaluation of approaches to prevent medical overuse: Six items, e.g., “As a doctor, one should talk to one’s patients about the costs of tests and medication”.

Evaluation of “Choosing Wisely” advices for family physicians: Six items, e.g., “Don’t perform imaging for low back pain within the first six weeks unless red flags are present.”

Reasons for the questionnaire design chosen: GPs were asked to estimate the prevalence of medical overuse at the beginning of the survey (rather than at the end) in order to avoid bias caused by confronting them with the subject of medical overuse throughout answering the questionnaire. A Likert scale with an even number of categories was chosen so that our respondents had no neutral category and were forced to pick an option for or against an item [45]. Items were randomly assigned for each participant in the topics to prevent hidden biases due to the same item sequence presentation (order effect bias) [46]. In question three, participants had to select three of the most substantial causes suspected for medical overuse–so called forced choice question [45]. It was not possible to flip backwards in the questionnaire and modify items retrospectively in order to prevent social desirability bias [47]. GPs should not be able to modify answers based on an upcoming feeling that the authors have a preference which they want to hear. The full questionnaire is available as supplementary file.

Data analysis

Only completely answered questionnaires were included in the analysis. Statistical analyses were performed using SPSS, version 24 (IBM Statistics). The processing of the data was carried out in two steps: A descriptive analysis followed by an evaluation of group differences. For all items on the six-point Likert scale mean and standard deviation were computed. A box plot was chosen for graphical presentation.

Participants were grouped according to their demographic variables including gender (male vs. female), age (≤ 50 years vs. > 50 years) and practice volume (patients treated per physician per quarter (≤ 1000 vs. > 1000). In addition, respondents were grouped according to being interested or not being interested in the mentioned campaigns resulting in two groups: “Campaign interested GPs”, who had already heard at least of one campaign and “non-interested GPs”, who had heard of none. A similar approach was chosen by Kost et al. [24].

Differences between groups were assessed in regard to the main topics of the questionnaire: “General assessment of medical overuse” (section A) and “Personal attitudes towards medical overuse” (section B). For section B, a sum score for each of the four subtopics was built. A sum score is defined as the sum of all numerical item values per participant summed up in one topic of the questionnaire [42]. For a reasonable and homogeneous interpretation of the sum score, all items must have the same item polarization [43]. Therefore, we exchanged the scale endpoints of the items 5.1, 5.12, 6.1, 6.3 and 6.4. Cronbachs Alpha was used to test whether a sum score for each subtopic was reasonable (see below). Cronbachs Alpha is low for two subtopics, which in part might be due to the low number of items per subtopic. A higher sum score indicated:

higher tendency to justify medical overuse (topic 5): Cronbachs α = 0.64, sum score range (R) = 13–78,

higher rating of relevance and frequency (topic 6): Cronbachs α = 0.55, sum score range (R) = 6–36

higher acceptance of proposed solutions for preventing medical overuse (topic 7): Cronbachs α = 0.39, sum score range (R) = 6–36

higher acceptance of Choosing wisely advices (topic 8): Cronbachs α = 0.71, sum score range (R) = 6–36

Groups were compared using Students t-Tests.

Results

Descriptive analysis

Response rate: We invited 750 practices via email to participate and received 155 (21%) questionnaires of which 135 (87%) were fully completed, resulting in a response rate of 18% that could be used for data analysis.

The mean age of participants was 54 years (SD = 8), 79% were male and 92% were trained GPs. The majority (68%) had professional experience as a GP for over 15 years. Approximately half of the participants regarded their doctor’s office to be located in an urban area (51%) and almost two thirds (65%) had a practice volume of more than 1.000 patients per quarter. Demographic data can also be seen in Table 1.

Table 1

Demographic data of respondents.

		N	%
Gender	Male	106	79%
	Female	29	22%
Age	≤ 50 years	44	33%
	> 50 years	91	67%
Professional title	GP	124	92%
	Specialist for internal medicine (working as GP)	9	7%
	Non-specialist medical doctor	1	1%
	GP trainee	1	1%
Professional experience	≤ 15 years	43	32%
	> 15 years	92	68%
Area of work	Urban	69	51%
	Rural	66	49%
Practice volume	≤ 1.000	47	35%
	> 1.000	88	65%

Information on the demographics about the entire population of GPs in Northern Bavaria are provided by the Bavarian Association of Statutory Health Insurance Physicians (Bavarian ASIP, described above). In the entire population, mean age is 55.3 years and 64% are male. That is, our sample was only slightly younger and had higher percentage of men.

A. General assessment of medical overuse

Frequency estimation of medical overuse: Around 38% of medical services were considered as overuse.

Perceived need for action: Medical underuse or overuse: Nearly half (47%) of the respondents judged medical overuse to be the more important problem. For 28% it was more important to tackle medical underuse.

Presumed causes for medical overuse: Factors contemplated most frequently were “patients´ expectations” (76%), “lack of a primary care system” (61%), and “defensive medicine” (53%), whereas “disregard of evidence/guidelines” (15%) and “economic pressure on the side of the doctor” (13%) appeared least frequently. Results can also be seen in Table 2.

Table 2

Frequency of presumed causes for medical overuse ().

	Relative frequency
1. Patients´ expectations	76%
2. Lack of primary care system	61%
3. Defensive medicine	53%
4. Disease mongering	34%
5. Marketing of the pharmaceutical industry	27%
6. Progress in medical technology	22%
7. Disregard of evidence/guidelines	15%
8. Economic pressure on the side of the doctor	13%

Campaign awareness and interest: Half of the participants (50%) had never heard of the campaigns. “Choosing wisely” was known to 32%, of whom 88% stated that they had also used it. The German offshoot “Klug entscheiden” was known to 30%, of which 80% had already taken a closer look at the respective items. Results can be seen in Table 3.

Table 3

Campaign awareness and interest.

	Campaign interested GPs, that is the proportion of all GPs that are being aware of a campaign	The proportion of those also being familiar with the campaign or who had used at least elements of a certain campaign
Choosing wisely	32%	88%
Smarter medicine	4%	17%
Less is more	19%	44%
Klug entscheiden	30%	80%
Quaternary prevention	18%	50%
None of these campaigns	50%	/

Selected results are shown below. All results are depicted in Figs 1 to 3.

Fig 1

Descriptive analysis of items on personal attitudes to medical overuse (Item 5.1 to Item 5.13).

For each item, mean value and standard deviation are presented. A box plot for each item is shown in the last column. It consists of the minimum and maximum, the interquartile range and the median. The black dot represents the mean.

Fig 3

Descriptive analysis of items on personal attitudes to medical overuse (Item 8.1 to Item 8.6).

For each item, mean value and standard deviation are presented. A box plot for each item is shown in the last column. It consists of the minimum and maximum, the interquartile range and the median. The black dot represents the mean.

Descriptive analysis of items on personal attitudes to medical overuse (Item 6.1 to Item 6.6 and Item 7.1 to Item 7.6).

Tendency to justify medical overuse: Most of the doctors perceived that patients with unspecific back pain seemed dissatisfied if their symptoms were not being checked via diagnostic imaging (Item 5.4, M = 4.1, SD = 1.4). The majority agreed that patients associated competence with performing more diagnostic tests (Item 5.5, M = 3.8, SD = 1.3) and that they want to figure out the causes for symptoms as soon as possible (Item 5.13, M = 4.7, SD = 1.1.). A high proportion admit that defensive medicine leads to medical overuse (Item 5.8, M = 4.7, SD = 1.3). A majority of GPs agreed to the statement that they already have “decided against therapeutic measures, even though the newly implemented lower threshold would have suggested treatment of some form" (Item 5.12, M = 4.5; SD = 1.6).

Perceived relevance of medical overuse: A majority was aware of incidental findings and related problems (Item 6.5, M = 4.2; SD = 1.4). Doctors mostly agreed to the statement of knowing patients being harmed by medical overuse (Item 6.6, M = 4.3; SD = 1.7). At the same time, a high proportion acknowledged that “The topic of medical overuse is mostly overlooked in medical discussions.” (Item 6.1, M = 4.1; SD = 1.5).

Evaluation of approaches to prevent medical overuse: GPs supported further action of politics by mostly agreeing with the item “More political engagement is necessary in order to counteract medical overuse effectively.”(Item 7.2, M = 4.6; SD = 1.4). The gatekeeper role was considered important to almost all respondents (Item 7.3, M = 5.2; SD = 1.0). Finally, a high proportion emphasized the role of long professional experience in avoiding medical overuse (Item 7.4; M = 5.1; SD = 1.0).

Evaluation of “Choosing Wisely” advices for family physicians: Recommendations were well acknowledged as illustrated by high agreement rates for most of the recommendations. However, fewer doctors agreed to the recommendation “Don’t obtain blood chemistry panels or perform urine analyses for screening in asymptomatic, healthy adults” (Item 8.5; M = 3.1; SD = 1.8).

Group differences

Demographic variables: Most demographic variables did not show a significant influence on response patterns. Only a higher number of younger doctors (≤ 50 years) agreed to approaches to prevent medical overuse (t = 2.145, CI = [0.129; 3.191], p = 0.034). Results are also shown in Table 4.

Table 4

Results of general assessment of medical overuse and personal attitudes towards medical overuse of groups differing in gender, age and practice volume.

	Gender		Age		Practice volume
	Male	Female	≤ 50 years	> 50 years	≤ 1000 patients	> 1000 patients
Number (%)	106 (79%)	29 (22%)	47 (35%)	88 (65%)	44 (33%)	91 (67%)
A. General assessment of medical overuse
Frequency estimation of medical overuse M (%):	38	36	39	37	40	37
Need for action:
1. Medical overuse	47%	45%	51%	44%	39%	51%
2. Medical underuse	27%	38%	28%	28%	39%	23%
B. Personal attitude towards medical overuse
Tendency to justify medical overuse (sum score, range 13–78)	48	50	47	49	47	49
Relevance of medical overuse (sum score, range 6–36)	23	23	24	23	24	23
Approaches to prevent medical overuse (sum score, range 6–36)	27	26	28*	26*	28	27
“Choosing Wisely” advices (sum score, range 6–36)	29	27	30	28	24	23

Campaign awareness and interest: GPs interested in campaigns rated the necessity to avoid medical overuse higher than non-interested GPs (campaign interested GPs = 54%, non-interested GPs = 40%, p = 0.023). Non-interested GPs showed a higher tendency to justify medical overuse as compared to campaign interested GPs (sum score: non-interested GPs = 50 vs. campaign interested GPs = 47; p = 0.033). Campaign interested GPs showed a higher awareness of the relevance of medical overuse (sum score: non-interested GPs = 21, campaign interested GPs = 25, p = 0.001) and approval of “Choosing Wisely” recommendations (sum score: non-interested GPs = 26 vs. campaign interested GPs = 30, p = 0.001). Both groups rated patients´ expectations, lack of a primary care system and defensive medicine as most influential causes for medical overuse. The frequency of medical procedures considered as overuse was estimated only slightly higher by campaign interested GPs (campaign interested = 39% vs. non-interested GPs = 36%, p = 0.353). Results are depicted in Table 5.

Table 5

Results of general assessment of medical overuse and personal attitudes towards medical overuse of campaign-interested GPs vs. non-interested GPs.

	Non-interested GPs	Campaign interested GPs
A. General assessment of medical overuse
Amount (%)	68 (50%)	67 (50%)
Relative frequency estimation of medical overuse M (%)	36	39	t = 0.931, CI = [-9.204; 3.311], p = 0.353
Need for action:
1. Medical overuse	40%	54%	t = 2.307, CI = [-16.636; -1.279], p = 0.023
2. Medical underuse	31%	25%
B. Personal attitude towards medical overuse
Tendency to justify medical overuse (sum score, range 13–78)	50	47	t = 2.154; CI = [0.243; 5.703], p = 0.033
Relevance of medical overuse (sum score, range 6–36)	21	25	t = 4.508; CI = [-5.444; -2.123], p = 0.001
Approaches to prevent medical overuse (sum score, range 6–36)	27	27	t = 0.226; CI = [-1.626;1.293], p = 0.822
“Choosing Wisely” advices (sum score, range 6–36)	26	30	t = 4.09; CI = [-5.66; -1.966], p = 0.001

Discussion

Medical overuse was seen as a relevant problem that needs to be tackled, even though GPs agreed that overuse is barely discussed in the medical community. Also, knowledge of campaigns addressing medical overuse was limited. Nonetheless, recommendations given by the “Choosing Wisely” campaign were well accepted. Main drivers were seen in patients’ expectations, lack of a primary care system and defensive medicine. GPs did not rate the disregard of evidence by physicians as a main driver. Instead they accused a pressure to act by patients not accepting a “wait and see” approach. Active medical performing seems also to be attributed with more competence than non-acting. GPs agreed that incidental findings and widening of disease boundaries are a serious problem. Asked about possible solutions, GPs considered it a main political task to create conditions that help to prevent medical overuse. An important answer to tackle medical overuse was considered in the implementation of a primary care system.

Similar to findings from other countries, GPs in Germany regarded medical overuse as an important issue [35, 36]. Their conviction that patients are more satisfied and that doctors are considered as more competent through actions is well known as commission bias in medical decision making [48]. A study with patients suffering from chronic pain revealed that physicians’ refusal to prescribe opioids was attributed to distrust or lack of caring by some patients [49]. It seems possible that GPs are afraid that “watchful waiting” might also be attributed in a similar way and as a consequence interferes with the patient-doctor relationship. This fear together with fulfilling perceived patients’ expectations might lead to unnecessary medical procedures.

Consistent with other studies, main drivers of overuse were seen in factors outside GPs own responsibility [35, 36, 50]. It is known that attributing causes for failures or negative events to others helps in self-serving but is likely to prevent self-responsibility and behavior change [51]. It seems that medical overuse is mainly discussed by politics, health insurances and academic institutions, rather than by practicing physicians. The results of our study point to the importance of deeply involving practicing physicians in the discussion and in the process of defining causes and solutions of medical overuse. More effort will be needed to strengthen self-responsibility and commitment of GPs in a way that they feel confident to contribute to this issue.

The limited awareness of GPs for campaigns against medical overuse is not unusual [50, 52]. In our study, campaign interested GPs represented a more critical point of view with higher awareness of medical overuse. Asked about agreement with the recommendations of the “Choosing Wisely” campaigns, GPs mostly agreed with them. In addition, GPs agreed that guidelines should explicitly point out not to perform certain therapeutic or diagnostic services. Still it is somewhat surprising that the recommendation not to screen asymptomatic healthy individuals with blood or urine analyses was rejected. We assume that health checks are not only used to screen otherwise asymptomatic adults but were also seen as a possibility to check for medically unexplained symptoms. As long as nothing is found—which is usually the case—the patient is at ease. It seems that the contents of the campaigns are widely accepted in general, but need more and effective promotion to be implemented in everyday practice. As the perception of medical overuse was not affected by demographic variables, it seems that the attitude towards it is rather a question of personality than a question of age or gender. We might have to put more effort in identifying those early adopters in order to support them.

Strengths and limitations: Our study represents a first comprehensive empirical investigation to describe GPs’ views on medical overuse in Germany. The questionnaire was developed carefully, systematically and following the results of a qualitative study [27]. Response rate of 18% was limited in comparison to other surveys [36, 52]. Reasons might be the lack of incentive and/or a short recruitment time. Demographic variables were relatively close to the real distribution in the respective regions. GPs in our sample were slightly younger and proportion of men was higher. Nonetheless, findings should be interpreted with caution as generalization might be reduced. The voluntary participation and lack of financial compensation for participation can lead to a potential bias as it can be assumed that mostly GPs who are interested in medical overuse might have been more likely to respond to our questionnaire, skewing the sample. The study design did not allow observing the real behavior of the participants, but enables us to draw conclusions from attitudes to behavior.

Conclusion

German GPs perceive that medical overuse is a problem that needs to be solved. However, causes and solutions were mainly seen outside their own responsibility and reach. Our findings lead to the conclusion that GPs’ own contributions to medical overuse are neglected by them, maybe unconsciously. More effort is needed to increase awareness for medical overuse. Increasing awareness amongst medical students during medical education might be an important step forward. Also, greater efforts are needed to enhance self-efficacy and ownership regarding medical overuse.

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15 Oct 2019

PONE-D-19-23067

Is it really always only the others who are to blame? GP’s view on medical overuse.

A questionnaire study.

PLOS ONE

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Reviewer #1: Table 3 - Title of third column could be more specific to show difference from column 2. e.g. proportion of those who had used elements of the campaign

Lines 248-250 - Sentence needs to express idea more clearly

Limitations should include a comment on the low response rate; why this might be so e.g. response rates in electronic surveys by other authors; how this affects study; how this response rate might be improved in subsequent studies

Reviewer #2: The article is on an important topic area—overuse of medical services.

The article is written clearly, and the tables are well designed.

Overall, the authors followed a reasonable study design was followed. They used sound methods for developing and testing their questionnaire. The analysis has two deficits that can be amended before publication.

The used a registry of general practitioners (GPs) for sample selection. I was curious about why the authors limited their sample to GPs, as they noted that in Germany, unlike other countries, GPs do not serve as gatekeepers for access to medical specialists.

The study has two substantial methodological issues that limit the utility of the results. The authors followed sound survey procedures, with the exception of survey fielding. They only allowed 18 days for GPs to return the survey and sent out a single reminder. A longer data collection period and more follow-up probably would have improved the response rate.

Selection Bias. The study had a good sample plan, but only 18% of subjects returned complete questionnaires. An 18% response rate almost certainly entails some sort of selection bias. The authors mention that only respondents who are interested in the topic of medical overuse may have responded to the survey, although there is almost no way to test that. The authors report demographics for the physicians who returned the survey. I don’t know if they have access to demographics for the entire population of physicians in the geographic area, but if so, it would be helpful to compare the demographics of those who returned the survey with the entire population. While demographics would not tell much of a story about self-selection, it would be beneficial to know if there was selection by age or some other characteristic. In particular, since the authors found that younger doctors viewed medical overuse as more of a problem than older doctors, information on age of the sample compared with age of the population of GPs would have bolstered results.

Inefficient use of data. The questionnaire was comprised mainly of Likert-style questions on a scale of 1 to 6. The authors dichotomized responses into positive and negative. They provide no explanation about why they chose to do this, with the result that they lost information.

Suggestions for Revision

1. Compare the mean ages or age quartiles of survey respondents with the age of all GPs

2. Reanalyze the data without dichotomizing the Likert scales

**********

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Reviewer #1: No

Reviewer #2: No

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27 Nov 2019

Point-to-point-reply

PONE-D-19-23067

"Is it really always only the others who are to blame? GP’s view on medical overuse.

A questionnaire study.”

Dear Monika Asnani,

Please find below our response to reviewers’ comments. We would like to thank the two reviewers for their help in improving this manuscript. We have endeavoured to incorporate the recommendations in the revised version. Please find a detailed description of our revisions below. Line numbers refer to the document: 'Revised Manuscript with Track Changes'.

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

OUR RESPONSE: As will be described below, we have added additional information on distribution of age and sex of all GPs in the respective area (line 2017-220) and added a comment on the low response rates (line 367-375). We hope this will help to improve understanding and enable scientific conclusion.

________________________________________

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

Reviewer #1: Yes

Reviewer #2: No

OUR RESPONSE: As will be described below, data were reanalysed without dichotomizing the Likert Scales. We have decided to present mean values, standard deviations and in order to enable an overview of the distribution of the data at a glance we have added box plots for each item (see table 4 of the manuscript). We thank Reviewer #2 for his/her helpful recommendation.

________________________________________

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: No

OUR RESPONSE: The questionnaire in German and translated in English as well as anonymised data will be made available. Therefore, data availability statement will be changed as follows: “All relevant data are within the paper and its Supporting Information files.”.

________________________________________

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:

Table 3 - Title of third column could be more specific to show difference from column 2. e.g. proportion of those who had used elements of the campaign

OUR RESPONSE: Thank you for your advice. We added a more specific explanation in order to improve understanding. The new title of column 3 is as follows: “The proportion of those also being familiar with the campaign or who had used at least elements of a certain campaign.” (line number 245). We hope to clarify the difference between column 2 and 3.

Lines 248-250 - Sentence needs to express idea more clearly.

OUR RESPONSE: Thank you for your comment. Our description of the result may be misunderstood by readers. Therefore, we have decided to quote the item of the questionnaire verbatim. The sentence is now as follows: “A majority of GPs agreed to the statement that they already have “decided against therapeutic measures, even though the newly implemented lower threshold would have suggested treatment of some form" (Item 5.12, M = 4.5; SD = 1.6).” (line number 256-259).

Limitations should include a comment on the low response rate; why this might be so e.g. response rates in electronic surveys by other authors; how this affects study; how this response rate might be improved in subsequent studies.

OUR RESPONSE: We appreciate the comment and have added the following information in the discussion part: “Response rate of 18% was limited in comparison to other surveys [36, 52]. Reasons might be the lack of incentive and/or a short recruitment time. Demographic variables were relatively close to the real distribution in the respective regions. GPs in our sample were slightly younger and proportion of men was higher. Nonetheless, findings should be interpreted with caution as generalization might be reduced. The voluntary participation and lack of financial compensation for participation can lead to a potential bias as it can be assumed that mostly GPs who are interested in medical overuse might have been more likely to respond to our questionnaire, skewing the sample.” (line number 367-375).

Reviewer #2: The article is on an important topic area—overuse of medical services.

The article is written clearly, and the tables are well designed. Overall, the authors followed a reasonable study design was followed. They used sound methods for developing and testing their questionnaire. The analysis has two deficits that can be amended before publication.

They used a registry of general practitioners (GPs) for sample selection. I was curious about why the authors limited their sample to GPs, as they noted that in Germany, unlike other countries, GPs do not serve as gatekeepers for access to medical specialists.

OUR RESPONSE: Thank you for your comment. As stated in the introduction section, the GP’s role as a gate-keeper is weakened. Nonetheless, in case of health problems also in Germany most people go to their GP first. It also seems that the role of GPs as gate-keepers will be strengthening as health insurances provide family doctor-centred health care where patients have to go to their GP first. Also, in rural areas and for vulnerable populations, e.g., for persons with chronic conditions, patients with multimorbidity and of higher age, the GP is the most important physician and often the coordinator of care. Therefore, we see the GP in a central role to prevent medical overuse and decided to specifically ask them about their views and opinions regarding overtreatment.

The study has two substantial methodological issues that limit the utility of the results. The authors followed sound survey procedures, with the exception of survey fielding. They only allowed 18 days for GPs to return the survey and sent out a single reminder. A longer data collection period and more follow-up probably would have improved the response rate.

OUR RESPONSE: We thank for your comment. Short recruitment was due to our previous experience that response rate did not increase markedly after two invitations to participate. The following information have been added in the discussion part: Response rate of 18% was limited in comparison to other surveys [36, 52]. Reasons might be the lack of incentive and/or a short recruitment time. Demographic variables were relatively close to the real distribution in the respective regions. GPs in our sample were slightly younger and proportion of men was higher. Nonetheless, findings should be interpreted with caution as generalization might be reduced. The voluntary participation and lack of financial compensation for participation can lead to a potential bias as it can be assumed that mostly GPs who are interested in medical overuse might have been more likely to respond to our questionnaire, skewing the sample.” (line number 367-375).

Selection Bias. The study had a good sample plan, but only 18% of subjects returned complete questionnaires. An 18% response rate almost certainly entails some sort of selection bias. The authors mention that only respondents who are interested in the topic of medical overuse may have responded to the survey, although there is almost no way to test that. The authors report demographics for the physicians who returned the survey. I don’t know if they have access to demographics for the entire population of physicians in the geographic area, but if so, it would be helpful to compare the demographics of those who returned the survey with the entire population. While demographics would not tell much of a story about self-selection, it would be beneficial to know if there was selection by age or some other characteristic. In particular, since the authors found that younger doctors viewed medical overuse as more of a problem than older doctors, information on age of the sample compared with age of the population of GPs would have bolstered results.

OUR RESPONSE: Thank you for this recommendation. We added information regarding age and sex of the entire population of GPs within the respective area (line 217-220). Information is provided by the Bavarian Association of Statutory Health Insurance Physicians (https://www.kvb.de/fileadmin/kvb/dokumente/UeberUns/Versorgung/KVB-Versorgungsatlas_Hausaerzte.pdf Data from 2017 can be made available upon request).

Inefficient use of data. The questionnaire was comprised mainly of Likert-style questions on a scale of 1 to 6. The authors dichotomized responses into positive and negative. They provide no explanation about why they chose to do this, with the result that they lost information.

Suggestions for Revision

1. Compare the mean ages or age quartiles of survey respondents with the age of all GPs

2. Reanalyze the data without dichotomizing the Likert scales

OUR RESPONSE: We thank for this recommendation. As stated above,

(1) Age of all GPs is now described in the result section, line 217-220

(2) Data of all Likert scales were reanalysed without dichotomizing. Descriptive analyses now comprise presentation of mean values, standard deviation and also box plots for each item are shown.

19 Dec 2019

Is it really always only the others who are to blame? GP’s view on medical overuse. A questionnaire study.

PONE-D-19-23067R1

Dear Dr. Hueber,

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,

Monika R. Asnani, DM, PhD

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

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: All comments have been addressed

Reviewer #2: All comments have been addressed

**********

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: Yes

Reviewer #2: Yes

**********

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

Reviewer #1: Yes

Reviewer #2: 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: Yes

Reviewer #2: Yes

**********

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

Reviewer #2: 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: (No Response)

Reviewer #2: (No Response)

**********

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

Reviewer #2: No

23 Dec 2019

PONE-D-19-23067R1

Is it really always only the others who are to blame? GP’s view on medical overuse. A questionnaire study.

Dear Dr. Hueber:

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

Dr. Monika R. Asnani

Academic Editor

PLOS ONE