Plain language summary
Weight loss can benefit overweight and obese patients with type 2 diabetes mellitus (T2DM) with regards to cardiovascular risk factors, including glycaemic control. This systematic review and meta-analysis of 30 randomised controlled trials, including 7850 patients, aimed to evaluate racial/ethnic differences in response to lifestyle interventions for weight loss on glycosylated haemoglobin (HbA1c, a measure of glycaemic control) in overweight or obese patients with T2DM. Lifestyle interventions were associated with statistically significant reductions in HbA1c in White and Asian, but not in Black/African or Hispanic populations, although the latter were based on only 2 and 3 small trials, respectively, and may have therefore lacked statistical power. Reductions in HbA1c were seen in studies which led to a weight loss of more than 5% as well as those less than 5%, with greater reductions being seen in the former group. The authors conclude that ethnic differences should be taken into account when considering lifestyle interventions for diabetes management.
Abstract
AIMS: Weight reduction is fundamental for the management and remission of diabetes. We aimed to assess ethnic differences in the effects of lifestyle weight-loss interventions on HbA1c levels in overweight or obese adults with type 2 diabetes mellitus (T2DM). METHODS We systematically searched PubMed/MEDLINE and Web of Science online databases up to 31 Dec 2022. Randomized controlled trials using lifestyle weight-loss interventions in overweight or obese adults with T2DM were selected. We performed subgroup analyses to explore the heterogeneity across different ethnicities (Asians, White/Caucasians, Black/Africans and Hispanics). A random effects model was applied to calculate weighted mean difference (WMD) with 95% confidence interval (CI). RESULTS Thirty studies including 7580 subjects from different ethnicities were identified according to the predefined inclusion and exclusion criteria. HbA1c levels were significantly reduced by lifestyle weight-loss intervention. Notably, a significantly beneficial effect on HbA1c was observed in White/Caucasians (WMD = -0.59, 95% CI: -0.90, -0.28, P < 0.001) and Asians (WMD = -0.48, 95% CI: -0.63, -0.33, P < 0.001), but not in the Black/African or Hispanic group (both P > 0.05). The findings remained essentially unchanged in the sensitivity analysis. CONCLUSIONS Lifestyle weight-loss interventions had distinct beneficial effects on HbA1c levels in different ethnic groups with T2DM, especially in Caucasians and Asians.
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