Abstract
SummaryBackgroundEvidence exist that primary care referral to an open-group behavioural programme is an effective strategy for management of obesity, but little evidence on optimal intervention duration is available. We aimed to establish whether 52-week referral to an open-group weight-management programme would achieve greater weight loss and improvements in a range of health outcomes and be more cost-effective than the current practice of 12-week referrals.MethodsIn this non-blinded, parallel-group, randomised controlled trial, we recruited participants who were aged 18 years or older and had body-mass index (BMI) of 28 kg/m2 or higher from 23 primary care practices in England. Participants were randomly assigned (2:5:5) to brief advice and self-help materials, a weight-management programme (Weight Watchers) for 12 weeks, or the same weight-management programme for 52 weeks. We followed-up participants over 2 years. The primary outcome was weight at 1 year of follow-up, analysed with mixed-effects models according to intention-to-treat principles and adjusted for centre and baseline weight. In a hierarchical closed-testing procedure, we compared combined behavioural programme arms with brief intervention, then compared the 12-week programme and 52-week programme. We did a within-trial cost-effectiveness analysis using person-level data and modelled outcomes over a 25-year time horizon using microsimulation. This study is registered with Current Controlled Trials, number ISRCTN82857232.FindingsBetween Oct 18, 2012, and Feb 10, 2014, we enrolled 1269 participants. 1267 eligible participants were randomly assigned to the brief intervention (n=211), the 12-week programme (n=528), and the 52-week programme (n=528). Two participants in the 12-week programme had been found to be ineligible shortly after randomisation and were excluded from the analysis. 823 (65%) of 1267 participants completed an assessment at 1 year and 856 (68%) participants at 2 years. All eligible participants were included in the analyses. At 1 year, mean weight changes in the groups were −3·26 kg (brief intervention), −4·75 kg (12-week programme), and −6·76 kg (52-week programme). Participants in the behavioural programme lost more weight than those in the brief intervention (adjusted difference −2·71 kg, 95% CI −3·86 to −1·55; p<0·0001). The 52-week programme was more effective than the 12-week programme (−2·14 kg, −3·05 to −1·22; p<0·0001). Differences between groups were still significant at 2 years. No adverse events related to the intervention were reported. Over 2 years, the incremental cost-effectiveness ratio (ICER; compared with brief intervention) was £159 per kg lost for the 52-week programme and £91 per kg for the 12-week programme. Modelled over 25 years after baseline, the ICER for the 12-week programme was dominant compared with the brief intervention. The ICER for the 52-week programme was cost-effective compared with the brief intervention (£2394 per quality-adjusted life-year [QALY]) and the 12-week programme (£3804 per QALY).InterpretationFor adults with overweight or obesity, referral to this open-group behavioural weight-loss programme for at least 12 weeks is more effective than brief advice and self-help materials. A 52-week programme produces greater weight loss and other clinical benefits than a 12-week programme and, although it costs more, modelling suggests that the 52-week programme is cost-effective in the longer term.FundingNational Prevention Research Initiative, Weight Watchers International (as part of an UK Medical Research Council Industrial Collaboration Award).
Highlights
The burden of disease attributable to excess bodyweight places considerable strain on health-care resources across the world.[1,2] Behavioural weight-management programmes are the first-line method to aid weight loss in people who are overweight or obese, and there is good evidence that some programmes can be effective, other programmes have not been shown to be effective.[3]
Added value of this study We found that referral to a commercial, open-group behavioural programme for 12 weeks or 52 weeks resulted in more weight loss than a brief self-help intervention
We show for the first time that, over a 25-year period, the 12-week programme is cost-saving compared with a brief intervention, and that the 52-week programme is costeffective compared with the 12-week programme
Summary
The burden of disease attributable to excess bodyweight places considerable strain on health-care resources across the world.[1,2] Behavioural weight-management programmes are the first-line method to aid weight loss in people who are overweight or obese, and there is good evidence that some programmes can be effective, other programmes have not been shown to be effective.[3]. Evidence before this study A systematic review and meta-analysis was done in November, 2012, to synthesise data from 37 trials of behavioural weight-management programmes delivered in a context that could be replicated in routine clinical practice. The quality of the evidence was assessed as moderate These interventions lasted 12, 52, and 104 weeks with no studies comparing effectiveness with different durations of treatment. Indirect comparisons across all 37 studies found no effect of duration of intervention on weight loss at 12 months. Findings from a previous systematic review and meta-analysis of direct comparisons between interventions of different lengths, mostly from controlled research studies, showed that interventions providing extended care led to 3·2 kg less weight regain than control interventions over a mean follow-up period of 17·6 months after initial weight loss. We did an updated search of PubMed and Scopus with search terms for “overweight” and “obesity”, “diet” and “exercise”, and “weight-loss interventions”, for papers published up until Jan 12, 2017, and found no new direct comparisons of treatment duration
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