Aims: To review the evidence on interventions for reversing metabolic syndrome or preventing development of type 2 diabetes and cardiovascular disease in people with metabolic syndrome.

Methods: A systematic review and Bayesian mixed treatment comparison meta‐analysis was conducted. Relevant electronic bibliographic databases were searched up to January 2010. Included studies were randomized controlled trials with a follow‐up of ≥24 weeks and outcomes comparing incidence of diabetes and/or cardiovascular disease, or reversal of metabolic syndrome.

Results: A total of 16 studies met the inclusion criteria. Thirteen studies with outcome data for reversal of metabolic syndrome, involving 3907 participants, were included in the meta‐analysis. Insufficient trials reported cardiovascular events/mortality, or incidence of type 2 diabetes, to conduct a meta‐analysis for these outcomes. Interventions, alone or in combination, included lifestyle (diet and/or exercise) and pharmacological therapy. Using random‐effect models, both lifestyle (odds ratio, OR 3.81; 95% confidence interval, CI 2.47–5.88) and pharmacological interventions (OR 1.59; 95% CI 1.04–2.45) were statistically superior compared with control for reversing metabolic syndrome. Using mixed treatment comparison methods, the probability that lifestyle interventions were the most clinically effective was 87%.

Conclusions: Evidence suggests that both lifestyle and pharmacological interventions can reverse metabolic syndrome. However, there is a lack of data on whether these benefits are sustained and translate into longer term prevention of diabetes and/or cardiovascular disease.