Objective: To examine the effectiveness of behavioural weight management interventions for adults with obesity delivered in primary care. Design: Systematic review and meta-analysis of randomised controlled trials. Eligibility criteria for selection of studies: Randomised controlled trials of behavioural weight management interventions for adults with a body mass index ≥25 delivered in primary care compared with no treatment, attention control, or minimal intervention and weight change at ≥12 months follow-up. Data sources: Trials from a previous systematic review were extracted and the search completed using the Cochrane Central Register of Controlled Trials, Medline, PubMed, and PsychINFO from 1 January 2018 to 19 August 2021. Data extraction and synthesis: Two reviewers independently identified eligible studies, extracted data, and assessed risk of bias using the Cochrane risk of bias tool. Meta-analyses were conducted with random effects models, and a pooled mean difference for both weight (kg) and waist circumference (cm) were calculated. Main outcome measures: Primary outcome was weight change from baseline to 12 months. Secondary outcome was weight change from baseline to ≥24 months. Change in waist circumference was assessed at 12 months. Results: 34 trials were included: 14 were additional, from a previous review. 27 trials (n=8000) were included in the primary outcome of weight change at 12 month follow-up. The mean difference between the intervention and comparator groups at 12 months was-2.3 kg (95% confidence interval-3.0 to-1.6 kg, I2=88%, P<0.001), favouring the intervention group. At ≥24 months (13 trials, n=5011) the mean difference in weight change was-1.8 kg (-2.8 to-0.8 kg, I2=88%, P<0.001) favouring the intervention. The mean difference in waist circumference (18 trials, n=5288) was-2.5 cm (-3.2 to-1.8 cm, I2=69%, P<0.001) in favour of the intervention at 12 months. Conclusions: Behavioural weight management interventions for adults with obesity delivered in primary care are effective for weight loss and could be offered to members of the public. Systematic review registration: PROSPERO CRD42021275529.
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