Type 2 diabetes complications in ethnic minority compared with European host populations: a systematic review and meta-analysis

This systematic review and meta-analysis aimed to quantify differences in type 2 diabetes (T2D) complications between ethnic minority populations and European host populations, in both cross-sectional and prospective studies. Following Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines, we searched multiple databases for studies (until July 1, 2024) with T2D complications as outcome. Studies were included if they compared ethnic minority populations to the host population and were conducted in Europe. T2D complications included mortality, macrovascular and microvascular complications and mental disorders. Risk of bias was assessed with the assessment tool for observational cohort and cross-sectional studies. Risk estimates were pooled using random effects models. From a total of 2901 references, 58 studies were included, comprising 805 to 1 230 410 individuals for the meta-analyzed complications. Compared with the host population, ethnic minority populations generally had a lower risk of all-cause mortality (RR 0.70 (95% CI 0.63; 0.77); I2=87%)) and macrovascular complications (RR 0.72 (95% CI 0.58; 0.88); I2=88%). South Asians, however, showed comparable risks for most macrovascular complications and a slighthly higher risk of major adverse cardiovascular events. Increased risks for microvascular complications, nephropathy and retinopathy were observed (eg, in prospective studies RR 1.50 (95% CI 1.14; 1.96); I2=86% for nephropathy). No ethnic differences were observed for mental disorders. Ethnic minority populations with T2D in Europe are generally at reduced risk of all-cause mortality and macrovascular complications, but at higher risk of nephropathy and retinopathy. Our findings may help to further identify high-risk populations and to develop guidelines and future interventions. PROSPERO registration number:PROSPERO 2022 CRD42022366854.