Educational weight loss interventions in obese and overweight adults with type 2 diabetes: a systematic review and meta-analysis of randomized controlled trials

Abstract

Aim: The worldwide prevalence of type 2 diabetes mellitus is increasing, with most individuals with the disease being overweight or obese. Weight loss can reduce disease-related morbidity and mortality and weight losses of 10–15 kg have been shown to reverse type 2 diabetes. This review aimed to determine the effectiveness of community-based educational interventions for weight loss in type 2 diabetes. Methods: This is a systematic review and meta-analysis of randomized controlled trials (RCT) in obese or overweight adults, aged 18–75 years, with a diagnosis of type 2 diabetes. Primary outcomes were weight and/or BMI. CINAHL, MEDLINE, Embase, Scopus and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched from inception to June 2019. Trials were classified into specified a priori comparisons according to intervention type. A pooled standardized mean difference (SMD) (from baseline to follow-up) and 95% confidence intervals (95% CI) between trial groups (difference-in-difference) were estimated through random-effects meta-analyses using the inverse variance method. Heterogeneity was quantified using I2 and publication bias was explored visually using funnel plots. Results: Some 7383 records were screened; 228 full-text articles were assessed and 49 RCTs (n = 12 461 participants) were included in this review, with 44 being suitable for inclusion into the meta-analysis. Pooled estimates of education combined with low-calorie, low-carbohydrate meal replacements (SMD = –2.48, 95% CI –3.59, –1.49, I2 = 98%) or diets (SMD = –1.25, 95% CI –2.11, –0.39, I2 = 95%) or low-fat meal replacements (SMD = –1.15, 95%CI –2.05, –1.09, I2 = 85%) appeared most effective. Conclusion: Low-calorie, low-carbohydrate meal replacements or diets combined with education appear the most promising interventions to achieve the largest weight and BMI reductions in people with type 2 diabetes.