Effectiveness of lifestyle-based weight loss interventions for adults with type 2 diabetes: A systematic review and meta-analysis

Ten studies were included for review. Some heterogeneity was present in the sample, thus random-effects models were used to calculate pooled effects. Results: Intervention duration ranged from 16-weeks to nine years, with all but one delivered via individual or group face-to-face sessions. From six studies comparing lifestyle intervention to usual care the pooled effect on weight (n=5,795) was -3.33kg (95% CI: -5.06, -1.60kg), and on HbA1c (n=5,784) was -0.29% (95% CI: -0.61, 0.03%), with both attenuated in sensitivity analyses. The pooled within-group effect on weight (n=3,063) from all ten lifestyle intervention groups was -5.33kg (95% CI: -7.33, -3.34kg), also attenuated in sensitivity analyses. No participant or intervention characteristic examined explained the heterogeneity. Only one study assessed whether intervention effects were maintained following the end-of-intervention. Conclusions: Lifestyle-based weight loss intervention trials in type 2 diabetes achieve, on average, modest reductions in weight and HbA1c, but results were heavily influenced by one trial. Evidence-based approaches for improving the effectiveness of lifestyle-based interventions in type 2 diabetes are needed along with future studies reporting on maintenance and cost-effectiveness.