Tackling obesity in areas of high social deprivation: clinical effectiveness and cost-effectiveness of a task-based weight management group programme - a randomised controlled trial and economic evaluation.

weight loss advice by general practitioners and/or a referral to a practice nurse. Although this is helpful for some, more effective approaches that can be disseminated economically on a large scale are needed. Objective: To assess whether or not a task-based weight management programme [Weight Action Programme (WAP)] has better long-term effects than a 'best practice' intervention provided in primary care by practice nurses. Design: Randomised controlled trial with cost-effectiveness analysis. Setting: General practices in east London, UK. Participants: Three hundred and thirty adults with a body mass index (BMI) of >= 30 kg/m(2) or a BMI of >= 28 kg/m(2) plus comorbidities were recruited from local general practices and via media publicity. Those who had a BMI of > 45 kg/m(2), had lost > 5% of their body weight in the previous 6 months, were currently pregnant or taking psychiatric medications were excluded. Participants were randomised (2 : 1) to the WAP or nurse arms. Interventions: The WAP intervention was delivered in eight weekly group sessions that combined dietary and physical activity, advice and self-monitoring in a group-oriented intervention. The initial course was followed by 10 monthly group maintenance sessions open to all participants in this study arm. The practice nurse intervention (best usual care) consisted of four one-to-one sessions delivered over 8 weeks, and included standard advice on diet and physical activity based on NHS 'Change4Life' materials and motivational support. Main outcome measures: The primary outcome measure was weight change at 12 months. Secondary outcome measures included change in BMI, waist circumference and blood pressure, and proportion of participants losing at least 5% and 10% of baseline body weight. Staff collecting measurements at the 6-and 12-month follow-ups were blinded to treatment allocation. The primary outcome measure was analysed according to the intention-to-treat principle, and included all participants with at least one recorded outcome at either 1, 2, 6 or 12 months. The analysis employed a mixed-effects linear regression model, adjusted for baseline weight, age, sex, ethnicity, smoking status and general practice. The European Quality of Life-5 Dimensions-5 Levels questionnaire was completed and used to estimate quality-adjusted life-years (QALYs) within the cost-effectiveness analysis. Results: There were 330 participants (WAP arm, n = 221; nurse arm, n = 109; 72% women). A total of 291 (88%) participants (WAP arm, n = 194; nurse arm, n = 97) were included in the main analysis for the primary outcome. Weight loss at 12 months was greater in the WAP arm than in the nurse intervention arm [-4.2 kg vs. -2.3 kg; difference -1.9 kg, 95% confidence interval (CI) -3.7 to -0.1 kg; p = 0.04]. Participants in the WAP arm were more likely than participants in the nurse arm to have lost at least 5% of their baseline body weight at 12 months (41% vs. 27%; odds ratio 14.61, 95% CI 2.32 to 91.96; p = 0.004). The incremental cost-effectiveness ratio for WAP over and above the nurse arm is 7742 pound per QALY. Conclusions: A WAP delivered in general practice better promotes weight loss over 12 months than a best usual practice nurse-led weight loss programme.