Effects of a group-based weight management programme on anxiety and depression: A randomised controlled trial (RCT).

OBJECTIVES: The aim was to investigate the impact of a group-based weight management programme on symptoms of depression and anxiety compared with self-help in a randomised controlled trial (RCT).
METHOD: People with overweight (Body Mass Index [BMI]≥28kg/m2) were randomly allocated self-help (n = 211) or a group-based weight management programme for 12 weeks (n = 528) or 52 weeks (n = 528) between 18/10/2012 and 10/02/2014. Symptoms were assessed using the Hospital Anxiety and Depression Scale, at baseline, 3, 12 and 24 months. Linear regression modelling examined changes in Hospital Anxiety and Depression Scale between trial arms.
RESULTS: At 3 months, there was a -0.6 point difference (95% confidence interval [CI], -1.1, -0.1) in depression score and -0.1 difference (95% CI, -0.7, 0.4) in anxiety score between group-based weight management programme and self-help. At subsequent time points there was no consistent evidence of a difference in depression or anxiety scores between trial arms. There was no evidence that depression or anxiety worsened at any time point.
CONCLUSIONS: There was no evidence of harm to depression or anxiety symptoms as a result of attending a group-based weight loss programme. There was a transient reduction in symptoms of depression, but not anxiety, compared to self-help. This effect equates to less than 1 point out of 21 on the Hospital Anxiety and Depression Scale and is not clinically significant.

Introduction

The effect of obesity on physical health has been well documented [1-5]. People with obesity are at greater risk of poor mental health than those without, but the reasons for this are complicated [6]. Recent evidence suggests that excess weight is associated with severity of depressive symptoms and potential biological mechanisms for this relationship have been explored [7, 8]. Other studies show that intentional weight loss can reduce symptoms of depression, [9, 10] or improve quality of life scores, [11] although this result is inconsistent, with some studies finding no evidence of a relationship between intentional weight loss and health related quality of life scores [12-14]. Further clarification of this relationship is important as there is an outstanding concern that weight loss attempts could worsen mental health [15].

The COVID-19 pandemic highlighted the importance of preventing and managing obesity. Excess weight is associated with an increased risk of hospitalisation, admission to intensive care and death from COVID-19 [16, 17]. This has led to interest in the potential for interventions to treat obesity to reduce the risk of adverse COVID-outcomes. In the UK, the National Institute for Clinical Excellence recently consulted on the addition of two new Quality and Outcomes Framework indicators, to be applied from 2021 [18]. These would financially incentivise referral from primary care of eligible adult patients to a weight management programme, resulting in a likely increase in number of patients accessing these services. Clarifying the effect that this may have on symptoms of depression and anxiety is of high importance if weight loss programmes are to be offered at scale.

The Weight loss Referrals for Adults in Primary Care [19] trial provides an opportunity to study the unconfounded effect of type of weight loss intervention provided on symptoms of depression/anxiety. A recent comprehensive systematic review highlighted larger transparent data sets, regular reporting, comparison with an appropriate inactive comparator group and longer follow up as a priority areas for future RCTs [20]. This data set offers unique insights into the longer term effects of group based weight loss programmes on symptoms of anxiety and depression due to the 24 month follow up. Measurements were taken at baseline, 3, 12 and 24 months, so changes in anxiety and depression scores were monitored over time. Participants were randomised to either a brief intervention encouraging a self-help approach (a realistic inactive comparator group), or a programme provided by a commercial weight loss provider over 12 or 52 weeks, so that confounding from other variables such as adverse life events and co-morbidities was mitigated. The aim was to examine the impact of group-based weight loss programmes on mental health, specifically symptoms of anxiety and depression, compared to self-directed weight loss attempts. The main analysis will explore the average impact on the population studied. However, there may be individual differences in who benefits and who experiences harm. Baseline levels of anxiety or depression is one such factor and subsequent analysis will investigate whether any effect is greater amongst those with higher depression or anxiety scores at baseline.

Methods

The WRAP trial protocol is described elsewhere [21]. In outline, this was a multicentre, non-blinded randomised controlled trial that recruited 1267 adults with overweight (BMI≥ 28 kg/m2) and randomised in a 2:5:5 allocation to either a brief intervention (BI) based around self-help; a 12-week commercial group-based weight loss programme (CP12); or a 52-week commercial group-based weight loss programme (CP52) respectively. The participants were selected through electronic patient records at 23 primary care practices across England between 18th October 2012 and 10th February 2014. Exclusion criteria included previous or planned bariatric surgery; planned (within 2 years) or current pregnancy; participation in a concurrent structured weight loss programme; eating disorders; non-English speakers or special communication needs; individuals with terminal illness or receiving palliative care; severe mental health problem, learning difficulty or dementia; a carer for a terminally ill individual or recently bereaved. The randomisation sequence was generated by the trial statistician at the time of protocol development and unknown to research staff and trial participants. Once participants were enrolled, the database revealed group allocation. Due to the nature of the intervention in the trial (attendance at a structured weight loss programme), participants and researchers could not be blinded to the intervention. Participants were followed up for a total of 24 months, completing the Hospital Anxiety and Depression Scale (HADS) at 0, 3, 12 and 24 months. The primary outcome was difference in mean weight change from baseline to 12 months between the three groups and this has been published elsewhere [22]. In line with previous analyses, an intention to treat analysis was conducted, in that all participants were included, regardless of their attendance at follow up or completion of questionnaires. The trial (number ISRCTN82857232) was registered with Current Controlled Trials and ethical approval was gained centrally at from NRES Committee East of England East and locally from NRES Committee South Central Oxford and NRES Committee North West Liverpool Central.

The intervention was either a 12- or 52-week local Weight Watchers programme, with a unique code to access digital tools to use throughout their programme. They were given a booklet of vouchers to exchange at each weekly visit (the same vouchers that are used in the UK National Health Service referral scheme) enabling participants to attend without charge. The brief intervention group were given a 32-page British Heart Foundation booklet of self-help weight management strategies. Research staff read from a script, explaining the structure and content of the booklet.

The HADS is a self-assessment scale consisting of 14 items which are each rated on a scale of 0–3 by the participant; 7 assess depression symptoms and 7 assess anxiety symptoms. The maximum score for both depression and anxiety is 21. A score of 0–7 is considered normal; 8–10 borderline; and 11–21 indicates the probable presence of depression or anxiety disorder. The HADS has a sensitivity and specificity of 0.8, comparable to the General Health Questionnaire and has been judged to perform well when assessing symptom severity in anxiety disorders and depression in a primary care setting [23]. We included data from completed questionnaires.

The data were analysed in Stata (Version 14.2) using mixed effects regression to calculate the differences between intervention (either 12-week or 52-week structured weight management programme) and control (brief intervention based around self-help) HADS at 3, 12 and 24 months. Sample size was calculated in the initial trial to detect the expected weight loss difference between the group-based weight loss programme and brief intervention arms (calculated at 1200 participants) [21]. We used three models to investigate sensitivity to missing data. As in the primary trial, the main analysis used a mixed model using a missing-at-random (MAR) assumption. Practice was added as a random effect and all other variables were fixed. Secondary analyses were conducted using multiple imputation and completers only (analysing participants who attended and completed HADS at every specified follow up).

Both stratified variables (centre and gender) and baseline anxiety or depression score were controlled for in the analysis. Participants in the 12-week and 52-week arms were analysed as a single group at the 12-week point, as both these arms received an identical group-based weight loss programme for the first 3 months. At 12 and 24 months, the data were analysed as a three-arm trial, because the 12-week arm had not received the group-based weight loss programme after 3 months, but the 52-week arm had. Secondly, we examined whether any effect would be greater in individuals with more severe symptoms at baseline using a term for interaction between randomisation group and baseline (anxiety or depression) score.

Results

The details of participant screening, eligibility and participation was published in the initial analysis and are summarised in Fig 1 [22]. As in the primary study, the total number of participants included in the analysis was 1267, and their baseline characteristics are summarised in Table 1. Overall, participants had a mean age of 53·2 years (standard deviation 13·8), mean BMI of 34·5 kg/m2 (5·2), 859 (68%) of 1267 participants were female, and 1136 (90%) were white. In the primary study, the mean weight change at 12 months was −3·26 kg (standard error 0·68) in brief intervention, −4·75 kg (0·35) in the 12-week programme, and −6·76 kg (0·42) in the 52-week programme [22]. Mean baseline HADS scores were 5.3 (standard deviation 3.6), and 7.2 (4.2) for depression and anxiety respectively, which both fall in the normal range.

Fig 1

CONSORT flow diagram for trial participants recruited between October 18, 2012 and February 10, 2014.

Table 1

Baseline characteristics of 1267 participants allocated to brief intervention or to commercial provider for 12 or 52 weeks.

	Brief Intervention (n = 211)		Commercial Provider: 12 weeks (n = 528)		Commercial Provider: 52 weeks (n = 528)
	n or n (%)	Mean (SD)	n or n (%)	Mean (SD)	n or n (%)	Mean (SD)
Age	211	51.9 (14.1)	528	53.6 (13.3)	528	53.3 (14.0)
Weight (kg)	211	96.1 (16.4)	528	96.6 (17.9)	528	95.7 (16.4)
Height (cm)	211	167 (9.5)	528	167 (8.9)	528	167 (9.0)
BMI (kg/m 2 )	211	34.4 (4.6)	528	34.7 (5.4)	528	34.5 (5.1)
Depression Score	201	5.6 (3.8)	505	5.3 (3.4)	507	5.2 (3.6)
Anxiety Score	201	7.5 (4.5)	505	7.0 (4.1)	507	7.4 (4.2)
Sex
Male	68 (32.2%)		171 (32.4%)		169 (32.0%)
Female	143 (67.8%)		357 (67.6%)		359 (68.0%)
Gross Household Income (per annum)
<£20 000	65 (30.8%)		125 (23.7%)		138 (26.1%)
£20 000–39 999	56 (26.5%)		132 (25.0%)		137 (26.0%)
≥£40 000	51 (24.2%)		132 (25.0%)		123 (23.3%)
Missing or prefer not to say	39 (18.5%)		139 (26.3%)		130 (24.6%)
Education
Higher degree or equivalent	23 (10.9%)		79 (15.0%)		68 (12.9%)
University degree or equivalent	48 (22.7%)		108 (20.5%)		97 (18.4%)
Post-secondary education	10 (4.7%)		14 (2.7%)		10 (1.9%)
A-Levels or equivalent	53 (25.1%)		95 (18.0%)		110 (20.8%)
GCSEs or equivalent	55 (26.1%)		153 (29.0%)		155 (29.4%)
None	7 (3.3%)		25 (4.7%)		27 (5.1%)
Missing or prefer not to say	15 (7.1%)		54 (10.2%)		60 (11.4%)
Ethnicity
Asian or Asian British	9 (4.3%)		11 (2.0%)		15 (2.8%)
Black or black British	5 (2.4%)		12 (2.3%)		6 (1.1%)
Mixed or multiple ethnic group	4 (1.9%)		4 (0.8%)		7 (1.3%)
White or white British	181 (85.8%)		480 (90.1%)		475 (90.0%)
Other	2 (0.9%)		6 (1.1%)		7 (1.3%)
Missing or prefer not to say	10 (4.7%)		15 (2.8%)		18 (3.4%)

All 1267 participants were included in the multiple imputation model. 1247 were included in the mixed model, as 20 participants had no recorded HADS at any time point. In the completers only analysis 897 (71%) were included at 3-month follow up, 727 (57%) at 12 months, and 728 (57%) at 24 months. Trajectories of the mean raw depression and anxiety scores at each time point are shown in Figs 2 and 3. Numerical details are provided in Table 2. At all time points, and across all arms, there was no evidence of harm.

Fig 2

Depression score over 24 months of follow-up.

Data are mean (standard error) of all measured HADS at each time point (Table 2).

Fig 3

Anxiety score over 24 months of follow-up.

Data are mean (standard error) of all measured HADS at each time point (Table 2).

Table 2

Change in anxiety and depression score from baseline by allocated programme.

BI: Brief intervention. CP12: 12-week commercial provider weight loss programme. CP52: 52-week commercial provider weight loss programme.

	BI (n = 211)			CP12 (n = 528)			CP52 (n = 528)			CP12 & CP52 (n = 1056)
	n	Mean HADS (SE)	Mean change in HADS from baseline (SE)	n	Mean HADS (SE)	Mean change in HADS from baseline (SE)	n	Mean HADS (SE)	Mean change in HADS from baseline (SE)	n	Mean HADS (SE)	Mean change in HADS from baseline (SE)
Depression Score
Baseline	201	5.6 (0.3)		505	5.3 (0.2)		507	5.2 (0.2)		1012	5.2 (0.1)
3 months	128	5.6 (0.3)	0.2 (0.2)	370	4.4 (0.2)	-0.6 (0.1)	427	4.6 (0.2)	-0.4 (0.1)	797	4.5 (0.1)	-0.5 (0.1)
12 months	105	5.5 (0.4)	0.3 (0.3)	315	4.5 (0.2)	-0.4 (0.2)	329	4.6 (0.2)	-0.3 (0.2)
24 months	112	5.1 (0.4)	-0.3 (0.3)	315	5.1 (0.2)	0.1 (0.2)	321	4.8 (0.2)	0.0 (0.2)
Anxiety Score
Baseline	201	7.5 (0.3)		505	7.0 (0.2)		507	7.4 (0.2)		1012	7.2 (0.1)
3 months	128	7.1 (0.4)	-0.3 (0.2)	370	6.4 (0.2)	-0.5 (0.1)	427	6.8 (0.2)	-0.4 (0.1)	797	6.6 (0.2)	-0.4 (0.1)
12 months	105	7.0 (0.4)	0.0 (0.3)	315	6.3 (0.2)	-0.3 (0.2)	329	7.0 (0.3)	0.0 (0.2)
24 months	112	6.5 (0.4)	-0.5 (0.3)	315	6.8 (0.2)	0.2 (0.2)	321	7.0 (0.2)	0.0 (0.2)

At three months, the combined group-based programmes reduced depression score by -0.6 (95% confidence interval, -1.1, -0.1) compared with brief intervention in the mixed model. There was no evidence of a difference between the 12-week programme and brief intervention at 12 [-0.5 (-1.0, 0.1)] or 24 months follow up [0.5 (-0.1,1.0)], or between the 52-week programme and brief intervention at either 12 [-0.5 (-1.1, 0.1)] or 24 months follow-up [0.2 (-0.3, 0.8)] (Table 3).

Table 3

Change in anxiety and depression score during a 12-week commercial provider (CP12) and 52-week commercial provider (CP52) weight loss programme compared to brief intervention (BI).

	CP12 vs. BI		CP52 vs. BI		CP12 & CP52 vs. BI
	Mean adjusted difference* (95% CI)	p value**	Mean adjusted difference* (95% CI)	p value**	Mean adjusted difference* (95% CI)	p value**
Depression
Mixed-effects model (n = 1247)
3 months					-0.6 (-1.1, -0.1)	0.01
12 months	-0.5 (-1.0, 0.1)	0.12	-0.5 (-1.1, 0.1)	0.09
24 months	0.5 (-0.1, 1.0)	0.10	0.2 (-0.3, 0.8)	0.42
Completers Only
3 months (n = 897)					-0.8 (-1.3, -0.3)	<0.01
12 months (n = 727)	-0.7 (-1.3, -0.1)	0.02	-0.7 (-1.3, -0.1)	0.03
24 months (n = 728)	0.4 (-0.2, 1.0)	0.21	0.2 (-0.4, 0.8)	0.49
Multiple Imputation (n = 1267)
3 months					-0.8 (-1.2, -0.3)	<0.01
12 months	-0.5 (-1.1, 0.1)	0.09	-0.5 (-1.1, 0.0)	0.07
24 months	0.3 (-0.3, 0.9)	0.33	0.2 (-0.4, 0.8)	0.57
Anxiety
Mixed-effects model (n = 1247)
3 months					-0.1 (-0.7, 0.4)	0.69
12 months	-0.2 (-0.8, 0.5)	0.63	-0.1 (-0.7, 0.4)	0.69
24 months	0.7 (0.0, 1.3)	0.04	0.5 (-0.2, 1.1)	0.15
Completers Only
3 months (n = 897)					-0.2 (-0.7, 0.3)	0.53
12 months (n = 727)	-0.4 (-1.0, 0.3)	0.28	0.1 (-0.7, 0.6)	0.87
24 months (n = 728)	0.6 (-0.1, 1.3)	0.10	0.4 (-0.2, 1.1)	0.20
Multiple Imputation (n = 1267)
3 months					-0.1 (-0.6, 0.4)	0.70
12 months	-0.2 (-0.8, 0.5)	0.57	0.2 (-0.5, 0.8)	0.61
24 months	0.6 (-0.1, 1.3)	0.07	0.5 (-0.1, 1.1)	0.13

*adjusted for centre, gender, baseline depression and baseline anxiety score as appropriate

**unadjusted p value.

These results were replicated in the multiple imputation model. In the completers only model, the combined group-based weight loss programme reduced depression score by -0.8 (-1.3, -0.3), compared with the brief intervention. This persisted at 12 months between the 12-week programme and brief intervention [-0.7 (-1.3, -0.1)] and between the 52-week programme and brief intervention [-0.7 (-1.3, -0.1)]. As in the mixed effects and multiple imputation model, there was no evidence of a difference between arms in the completers only model at 24 months [12-week programme vs brief intervention = 0.4 (-0.2, 1.0); 52-week programme vs brief intervention = 0.2 (-0.4, 0.8)]. The results for anxiety showed similarly small and mostly non-significant differences between arms (Table 3). We also examined whether the effect of treatment on the outcome varied by extent of anxiety/depression at baseline. In all models examined (completers only and multiple imputation) there was no evidence of interaction (p>0.05) at any time point.

Discussion

The trial was large enough to give precise estimates that excluded the possibility that these programmes lead to clinically relevant worsening of depression or anxiety. Referral to an open-group behavioural weight loss programme resulted in a statistically significant though small decrease in depression symptoms from baseline to 3 months compared with the brief intervention arm, but there was no consistent evidence of effect at 12 or 24 months (evidence of effect at 12 months completers only, but not multiple imputation or mixed model analysis). There was no evidence that allocation to group support rather than self-guided weight loss influenced symptoms of anxiety. The mean scores for all groups did not vary much over time, including at 24 months when weight regain had taken place. There was no evidence that the effects of weight loss treatment depended on the degree of depression or anxiety symptoms present at baseline.

A strength of this trial was the generalisability to the UK population. Participants were recruited from multiple centres (Oxford, Cambridge and Liverpool) with over half of the participating GP practices from areas with an index of multiple deprivation score above the UK average [19]. The overall ethnic diversity of participants reflects the UK population. The study participants had a mean BMI of 34.5kg/m2 which is typical of the average BMI of patients referred to group weight management programmes in the NHS [24]. We used an intention-to-treat analysis to model real world clinical practice and to produce conservative estimates of effect.

Although the loss to follow up was below the anticipated dropout rate for weight loss trials, the addition of requiring a completed HADS questionnaire resulted in a slightly higher than average missing data at 12 and 24 months (43%) [25]. Results from the three different analysis models however showed a similar effect for both anxiety and depression scores in the MAR models and completers only model, illustrating the robustness of the analysis. Randomisation should distribute covariates equally between groups at baseline, however we cannot exclude post-randomisation bias, such as unequal distribution of pharmacotherapy or psychotherapy between groups after this. Another limitation was that only adults with a BMI ≥ 28 kg/m2were included. Adults with a BMI between 25–28 kg/m2 also have negative health consequences associated with excess weight [26]. Future weight management trials should consider expanding their inclusion criteria to fully incorporate overweight adults.

Our results concur with a recent comprehensive systematic review on the topic [20]. Both found participation in a group-based weight loss can reduce symptoms of depression compared to control, and no evidence of a difference in anxiety scores between arms. Few studies included in the systematic review documented anxiety score at 12 months or beyond, highlighting the need for longer term mental health follow up, as reported here. Similarly, both studies found no evidence that initiating a weight loss attempt resulted in an increase in symptoms of depression or anxiety as has previously been reported in observational studies [14].

These results show that there may be a small additional benefit to mental health of referring patients to group-based weight loss programmes. However, the clinical significance of this effect is likely to be minimal. At 3 months, when the maximal reduction in depression score was observed in the group-based weight loss programme compared to the brief intervention, there was less than one point difference on the HADS scale, where the maximum possible score is 21.

Although this study found no evidence of an interaction with baseline mental health scores, this group-based analysis cannot exclude the possibility that, particularly when offered at scale, some individuals may experience negative impacts on mental health of weight loss interventions. However, many people are currently trying to lose weight and this analysis provides reassurance that offering greater access to group-based programmes does not increase the risk of adverse effects on mental health.

Conclusion

In conclusion, healthcare professionals should be reassured that there is no evidence of an increase in symptoms of depression or anxiety up to two years after referring people to a group-based weight loss programme. On average, there may be a small, but clinically insignificant improvement in symptoms of depression for those referred to programmes with group support compared to self-help in the short-term.

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16 Apr 2021

PONE-D-21-01460

Effects of a group-based weight management programme on anxiety and depression: a randomised controlled trial (RCT)

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Reviewer #1: Thanks for the opportunity to revise this manuscript. The aim of the article was to investigate if a group-based weight management programme worsened anxiety and depression in a group of patients with overweight. The authors concluded that this programme can even ameliorate depressive symptoms in the short-term. These are my main observations about the methods and results of the present research article:

1) Why did the authors select 28 and not 25 as a BMI threshold for overweight?

2) I am not fully in agreement with some considerations in the introduction. It is well established that overweight and obesity are associated with severity of depressive symptoms (Milaneschi et al., 2019; doi: 10.1038/s41380-018-0017-5). In this sense I wonder if the amelioration of depressive symptoms found in the short term for the group-based weight management programme is not due to a major efficacy in weight loss and in the consequent normalization of underlying biological abnormalities with respect to self-help group (Macchi et al., 2020; doi: 10.1186/s12933-020-01158-6). Were there any significant differences in the efficacy on weight loss between groups?

3) The reference (12) is improper as it refers to elderly patients with medical conditions and not affected by overweight.

4) The authors state that they excluded patients with severe mental disorders. However I wonder if some of the included subjects had a psychiatric disorder or were followed up by mental health professionals. Were there patients in treatment with psychotherapy or pharmacotherapy? This is an important confounding factor and it should be at least reported in study limitations if data are not available.

5) Looking at the results the authors state that mean baseline HADS scores fall in the normal range. However, if you take into account standard deviations, it is likely that some of these patients have clinically significant affective symptoms. Again I wonder if some of these patients received some type of treatment or were followed up by mental health professionals.

6) The authors report that they used mixed regression models for the analysis. Which were the random and fixed effects?

Reviewer #2: The manuscript entitled ‘Effects of a group-based weight management programme on anxiety and depression: a randomised controlled trial (RCT)’ with the aim to investigate the impact of a group-based weight management programme on symptoms of depression and anxiety compared with self-help in a randomised controlled trial.

This is quite an interesting study, however, the manuscript requires further improvement on the results presentations.

Method

Since the sample size was calculated earlier and published elsewhere it is to be cited.

Completers to be clearly defined.

Results

Table 1, at least 1 decimal point for percentages to be provided.

Table 2, for CP12 & CP52 (n=1056), what the mean change refers to be clearly denoted. The mean scores at each time period and baseline scores to be provided before deriving the mean change. Likewise with Table 3 prior to adjustment.

Table 3, technically the p value cannot be zero (to use symbol p <).

Page 15 Paragraph 1 Line 5 for follow-up [0.2 (-0.4, 0.8)]. In Table 3 it was stated [0.2 (-0.3, 0.8)]. Table 3 to be cited in the text.

Table 3 footnote, for ‘*adjusted for center, gender and baseline depression/anxiety score’ the symbol * to be inserted in the table and a separate adjustment to be denoted separately for each depression and anxiety. Decimal points to be standardized. Word mean to be added to Adjusted difference.

Information whether the p value was adjusted to be stated.

Figure 1 requires revision. Any dropouts to be placed or written outside the box. The time period of assessment to be stated.

Figure 2, n to be stated.

**********

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Reviewer #1: Yes: Prof. Massimiliano Buoli

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16 Jul 2021

Dear Professor Ruscica,

Many thanks for allowing us the opportunity to amend our manuscript. Please let the reviewers know that we are very grateful for their time in considering our study and providing valuable comments and suggestions to enhance its readability.

Please find below responses to the comments made by the two reviewers. The changes to the manuscript, highlighted in tracked change function, are uploaded separately as requested, in addition to the manuscript without tracked changes.

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We have followed these guidelines as described.

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

‘I have read the journal's policy and the authors of this manuscript have the following competing interests: PA and SAJ are investigators on an investigator-initiated trial funded by Cambridge Weight Plan. PA has done half a day’s consultancy for WW (formerly Weight Watchers). ALA is lead investigator on two publicly funded investigator-initiated trials where the intervention is provided by WW at no cost. None of these activities led to payments to the individuals named.'

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This has been updated and now reads: 'I have read the journal's policy and the authors of this manuscript have the following competing interests: PA and SAJ are investigators on an investigator-initiated trial funded by Cambridge Weight Plan.PA has presented at two symposia on behalf of the Royal College of General Practitioners that were sponsored by Novo Nordisk. ALA is lead investigator on two publicly funded investigator-initiated trials where the intervention is provided by WW at no cost. None of these activities led to payments to the individuals named. This does not alter our adherence to PLOS One policies on sharing data and materials.’

Funding

The trial was funded by the Medical Research Council National Prevention Research Initiative awarded to AA. Award number MR/J000493/1. The funding partners relevant to this award are (in alphabetical order): Alzheimer’s Research Trust, Alzheimer’s Society, Biotechnology and Biological Sciences Research Council, British Heart Foundation, Cancer Research UK, Chief Scientist Office, Scottish Government Health Directorate, Department of Health, Diabetes 15 UK, Economic and Social Research Council, Health and Social Care Research and Development Division of the Public Health Agency (HSC R&D Division), UK Medical Research Council (MRC), The Stroke Association, Welcome Trust, Welsh Assembly Government, and World Cancer Research Fund.

Weight Watchers donated free behavioural weight management programmes to the NHS to support the trial.

PA, SAJ, and RS are funded by National Institute for Health Research (NIHR) Oxford Biomedical Research Centre and NIHR Oxford and Thames Valley Applied Research Collaboration. LH is funded by an NIHR Academic Clinical Fellowship. There are no specific grant numbers associated with these awards.

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Many thanks for this comment. Our updated data sharing statement reads: ‘Participant consent only allows for data to be used in future research with appropriate ethical approval and data sharing agreements. As such, a managed data sharing process is necessary to ensure that the rights and expectations of participants are protected in line with GDPR. The host institution have an access policy (https://www.mrc-epid.cam.ac.uk/wp-content/uploads/2019/02/Data-Access-Sharing-Policy-v1-0_FINAL.pdf). Interested parties can obtain the data for replication or other research purposes by contacting the Principal Investigator Dr Amy Ahern at ala34@cam.ac.uk or contacting datasharing@mrc-epid.cam.ac.uk.’

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

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

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Reviewer #1: Yes

Reviewer #2: Partly

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

Reviewer #1: No

Reviewer #2: No

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Reviewer #1: Yes

Reviewer #2: Yes

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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: Thanks for the opportunity to revise this manuscript. The aim of the article was to investigate if a group-based weight management programme worsened anxiety and depression in a group of patients with overweight. The authors concluded that this programme can even ameliorate depressive symptoms in the short-term. These are my main observations about the methods and results of the present research article:

1) Why did the authors select 28 and not 25 as a BMI threshold for overweight?

We did not select 28 as a threshold to define overweight or obesity, but as a threshold where weight loss would benefit health. This is essentially as arbitrary as defining 25 or 30 as a threshold for inclusion, but we thought that 28 included people with excess adiposity without over-including those with a healthy amount of body fat.

2) I am not fully in agreement with some considerations in the introduction. It is well established that overweight and obesity are associated with severity of depressive symptoms (Milaneschi et al., 2019; doi: 10.1038/s41380-018-0017-5). In this sense I wonder if the amelioration of depressive symptoms found in the short term for the group-based weight management programme is not due to a major efficacy in weight loss and in the consequent normalization of underlying biological abnormalities with respect to self-help group (Macchi et al., 2020; doi: 10.1186/s12933-020-01158-. Were there any significant differences in the efficacy on weight loss between groups?

This is an interesting point that we think is worth including. The introduction has been reworded, with this in mind and referencing the papers suggested. This now reads: ‘The effect of obesity on physical health has been well documented [1-5]. People with obesity are at greater risk of poor mental health than those without, but the reasons for this are complicated[6]. Recent evidence suggests that excess weight is associated with severity of depressive symptoms and potential biological mechanisms for this relationship have been explored [7, 8]. Other studies show that intentional weight loss can reduce symptoms of depression, [9, 10] or improve quality of life scores, [11] although this result is inconsistent, with some studies finding no evidence of a relationship between intentional weight loss and health related quality of life scores [12-14]. Further clarification of this relationship is important as there is an outstanding concern that weight loss attempts could worsen mental health [15].’

Yes, there was a difference in the efficacy on weight loss between the groups. This was reported in the main trial (Ahern et al, 2017 https://doi.org/10.1016/S0140-6736(17)30647-5), but we agree this result is relevant to this secondary analysis, and so we have included this in the first paragraph of the results section: ‘In the primary study, the mean weight change at 12 months was −3·26 kg (standard error 0·68) in brief intervention, −4·75 kg (0·35) in the 12-week programme, and −6·76 kg (0·42) in the 52-week programme’.

3) The reference (12) is improper as it refers to elderly patients with medical conditions and not affected by overweight.

Many thanks for bringing this to our attention, this reference has been removed and the introduction rewritten as described above.

4) The authors state that they excluded patients with severe mental disorders. However I wonder if some of the included subjects had a psychiatric disorder or were followed up by mental health professionals. Were there patients in treatment with psychotherapy or pharmacotherapy? This is an important confounding factor and it should be at least reported in study limitations if data are not available

Yes, not all participants with a mental health diagnosis were excluded, and some participants had a diagnosed mild or moderate mental health condition with associated raised HADS score. Consequently, a large proportion of people would have been taking medication for mental illness at study start and throughout the study.

Although this presumably would influence scores, it would do so equally in the intervention and control groups. We have now added this to the discussion: ‘Randomisation should distribute covariates equally between groups at baseline, however we cannot exclude post-randomisation bias, such as unequal distribution of pharmacotherapy or psychotherapy between groups after this.’

5) Looking at the results the authors state that mean baseline HADS scores fall in the normal range. However, if you take into account standard deviations, it is likely that some of these patients have clinically significant affective symptoms. Again I wonder if some of these patients received some type of treatment or were followed up by mental health professionals.

Please see our response above. By including people with mental illness, we were able to ensure our results broadly represented the general population of people with overweight and obesity.

6) The authors report that they used mixed regression models for the analysis. Which were the random and fixed effects?

Practice was added as a random effect and all other variables were fixed and we have added that to the description of the analysis.

Reviewer #2: The manuscript entitled ‘Effects of a group-based weight management programme on anxiety and depression: a randomised controlled trial (RCT)’ with the aim to investigate the impact of a group-based weight management programme on symptoms of depression and anxiety compared with self-help in a randomised controlled trial.

This is quite an interesting study, however, the manuscript requires further improvement on the results presentations.

Method

Since the sample size was calculated earlier and published elsewhere it is to be cited.

This has now been updated and is cited.

Completers to be clearly defined.

We agree that this is confusing as currently stated. This has been elaborated on and now reads: ‘We used three models to investigate sensitivity to missing data. As in the primary trial, the main analysis used a mixed model using a missing-at-random (MAR) assumption, and secondary analyses were conducted using multiple imputation and completers only (analysing participants who attended and completed HADS at each specified follow up).’

Results

Table 1, at least 1 decimal point for percentages to be provided.

Agreed, this has now been changed.

Table 2, for CP12 & CP52 (n=1056), what the mean change refers to be clearly denoted. The mean scores at each time period and baseline scores to be provided before deriving the mean change. Likewise with Table 3 prior to adjustment.

We agree this should be changed for table 2. Table 2 has been edited to include mean scores and mean change. This now reads read ‘mean change in HADS from baseline’.

We have given the raw means and change in means in Table 2. However, our analysis focuses on analysing the trial outcome, where it is standard best practice to adjust in the analysis for factors used to stratify the randomisation and, where presenting change scores, adjust for baseline variables. It is not possible to present scores unadjusted for baseline score and it is not desirable to leave out the stratification factors (gender, centre). We trust the referee understands our choice of model selection, which was decided a priori by the design of the trial.

Table 3, technically the p value cannot be zero (to use symbol p <).

Agree, this has now been changed.

Page 15 Paragraph 1 Line 5 for follow-up [0.2 (-0.4, 0.8)]. In Table 3 it was stated [0.2 (-0.3, 0.8)]. Table 3 to be cited in the text.

Thank you for spotting this, we have now corrected it.

Table 3 footnote, for ‘*adjusted for center, gender and baseline depression/anxiety score’ the symbol * to be inserted in the table and a separate adjustment to be denoted separately for each depression and anxiety. Decimal points to be standardized. Word mean to be added to Adjusted difference.

The headings now read ‘Mean adjusted difference’, and the * has been appropriately inserted.

We have ensured all the number of decimal points are consistent. However, we do not believe it would be appropriate to give HADS to 2dp, or p value to 1dp.

Information whether the p value was adjusted to be stated.

There was no adjustment of the p value for multiple testing. This information has been added to the table.

Figure 1 requires revision. Any dropouts to be placed or written outside the box. The time period of assessment to be stated.

Many thanks for this feedback, this has been changed as described.

Figure 2, n to be stated.

We have added ‘Data are mean (standard error) of all measured HADS at each time point (Table 2)’ to direct the reader to the ‘n’ at each timepoint detailed in table 2.

Again, we would like to thank the reviewers for taking time to read our work and provide valuable comments. We hope the above changes are to your satisfaction. Please feel free to contact us should there be a need to clarify any of the comments above.

With many thanks and gratitude.

Dr Laura Heath, Professor Susan Jebb, Professor Richard Stevens, Dr Graham Wheeler, Dr Amy Ahern, Dr Emma Boyland, Professor Jason Halford and Professor Paul Aveyard

Submitted filename: Response to reviewers_final.docx

Click here for additional data file.

13 Dec 2021

4 Jan 2022

Many thanks for your further comments about our manuscript. We believe we have fully addressed these points below.

Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

Many thanks for highlighting this issue. Reference 16 (Hussain et al, 2020) has been removed from our reference list as this has been retracted. We have replaced this with a current, relevant reference (16):

‘Gao M, Piernas C, Astbury NM, Hippisley-Cox J, O'Rahilly S, Aveyard P, et al. Associations between body-mass index and COVID-19 severity in 6.9 million people in England: a prospective, community-based, cohort study. Lancet Diabetes Endocrinol. 2021;9(6):350-9. Epub 2021/05/02. doi: 10.1016/S2213-8587(21)00089-9. PubMed PMID: 33932335; PubMed Central PMCID: PMCPMC8081400’

Reference 20 has been updated. This was a preprint reference in the previous submission. This now reads:

‘Jones RA, Lawlor ER, Birch JM, Patel MI, Werneck AO, Hoare E, et al. The impact of adult behavioural weight management interventions on mental health: A systematic review and meta-analysis. Obes Rev. 2021;22(4):e13150. Epub 2020/10/27. doi: 10.1111/obr.13150. PubMed PMID: 33103340; PubMed Central PMCID: PMCPMC7116866’

I agree with the reviewer that high BMI accounted for 4.0 million deaths globally, nearly 40% of which occurred in persons who were not obese. Please address the concern raised.

Please see response below.

The authors largely improved their manuscript especially in the part of introduction.

On the other hand I am sorry but I still disagree with the authors because a BMI greater than 25 and therefore between 25 and 28 has negative effects on health. This aspect is explicitly reported in available literature (e.g. doi: 10.1056/NEJMoa1614362). This limitation of the study should be clearly mentioned in the text.

Many thanks for your comment. This limitation has now been explored in the discussion and the reference suggested is included in the manuscript.

Discussion, page 12 line 198-201

‘Another limitation was that only adults with a BMI ≥ 28 kg/m2were included. Adults with a BMI between 25-28 kg/m2 also have negative health consequences associated with excess weight.(1) Future weight management trials should consider expanding their inclusion criteria to fully incorporate overweight adults.’

References

1. Collaborators GBDO, Afshin A, Forouzanfar MH, Reitsma MB, Sur P, Estep K, et al. Health Effects of Overweight and Obesity in 195 Countries over 25 Years. N Engl J Med. 2017;377(1):13-27.

Submitted filename: Response to Reviewers.docx

Click here for additional data file.

17 Jan 2022

Effects of a group-based weight management programme on anxiety and depression: a randomised controlled trial (RCT)

PONE-D-21-01460R2

Dear Dr. Heath,

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

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Comments to the Author

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Reviewer #1: 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: (No Response)

**********

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

Reviewer #1: (No Response)

**********

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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 Response)

**********

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: (No Response)

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Reviewer #1: (No Response)

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Reviewer #1: Yes: Buoli Massimiliano

25 Jan 2022

PONE-D-21-01460R2

Effects of a group-based weight management programme on anxiety and depression: a randomised controlled trial (RCT)

Dear Dr. Heath:

I'm 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.

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