PT  - JOURNAL ARTICLE
AU  - Leslea Peirson
AU  - James Douketis
AU  - Donna Ciliska
AU  - Donna Fitzpatrick-Lewis
AU  - Muhammad Usman Ali
AU  - Parminder Raina
TI  - Treatment for overweight and obesity in adult populations: a systematic review and meta-analysis
AID  - 10.9778/cmajo.20140012
DP  - 2014 Oct 01
TA  - CMAJ Open
PG  - E306--E317
VI  - 2
IP  - 4
4099  - http://www.cmajopen.ca/content/2/4/E306.short
4100  - http://www.cmajopen.ca/content/2/4/E306.full
AB  - Background Obesity is a major public health issue. This review updates the evidence on the effectiveness of behavioural and pharmacologic treatments for overweight and obesity in adults. Methods We updated the search conducted in a previous review. Randomized trials of primary-care-relevant behavioural (diet, exercise and lifestyle) and pharmacologic (orlistat and metformin) with or without behavioural treatments in overweight and obese adults were included if 12-month, postbaseline data were provided for weight outcomes. Studies reporting harms were included regardless of design. Data were extracted and pooled wherever possible for 5 weight outcomes, 6 secondary health outcomes and 4 adverse events categories. Results We identified 68 studies, most consisted of short-term (≤ 12 mo) treatments using diet (n = 8), exercise (n = 4), diet and exercise (n = 10), lifestyle (n = 19), orlistat (n = 25) or metformin (n = 4). Compared with the control groups, intervention participants had a greater weight loss of −3.02 kg (95% confidence interval [CI] −3.52 to −2.52), a greater reduction in waist circumference of −2.78 cm (95% CI −3.34 to −2.22) and a greater reduction in body mass index of −1.11 kg/m2 (95% CI −1.39 to −0.84). The relative risk for loss of ≥ 5% body weight was 1.77 (95% CI 1.58–1.99, [number needed to treat 5, 95% CI 4–7]), and the relative risk for loss of ≥ 10% body weight was 1.91 (95% CI 1.69–2.16, [number needed to treat 9, 95% CI 7–12]). Incidence of type 2 diabetes was lower among pre-diabetic intervention participants (relative risk 0.62 [95% CI 0.50–0.77], number needed to treat 17 [95% CI 13–29]). With prevalence rates for type 2 diabetes on the rise, weight loss coupled with a reduction in the incidence of type 2 diabetes could potentially have a significant benefit on population health and a possible reduction in need for drug treatments for glycemic control. Interpretation There is moderate quality evidence that behavioural and pharmacologic plus behvioural, treatments for overweight and obesity in adults lead to clinically important reductions in weight and incidence of type 2 diabetes in pre-diabetic populations. Registration: PROSPERO no. CRD42012002753