Prevalence and incidence of complications at diagnosis of T2DM and during follow-up by BMI and ethnicity: a matched case–control analysis

AIMS: To estimate the risk of developing long-term major cardiovascular and renal complications in relation to levels of body mass index (BMI) in a population of White European (WE), African-Caribbean (AC), and South Asian (SA) patients with type 2 diabetes mellitus (T2DM). MATERIALS AND METHODS: Patients with new diagnosis of T2DM, aged ≥ 18 years from January 2000 (n = 69,436) and their age-sex-ethnicity matched non-diabetic controls (n = 272,190) were identified from UK primary care database. Incidence rates ratios (IRRs) for non-fatal major cardiovascular events (MACE) and chronic kidney disease (CKD) in patients with T2DM compared to controls were estimated using multivariate Mantel-Cox model. RESULTS: Among normal weight patients with T2DM, WEs had significantly higher prevalence of cardiovascular multi-morbidity (95% CI 9.5, 11.3), compared to SAs (95% CI 4.8, 9.5). AC and SA overweight and obese patients had similar prevalence, while obese WEs had significantly higher prevalence. During a median 7 years of follow-up, risk of MACE was significantly higher for overweight (95% CI of IRR 1.50, 2.46) and obese (95% CI of IRR 1.49, 2.43) SAs compared to their WE counterparts. However, similar risk levels were observed for normal weight WEs and SAs, respectively. Risk of CKD was higher and uniform for BMI ≥ 25 kg/m(2) amongst WEs and ACs, whereas only overweight patients had significantly higher risk of CKD amongst SA [IRR 2.08 (95% CI 1.49, 2.93)]. CONCLUSION: Risk of MACE/CKD varies over levels of BMI within each ethnic group, with overweight SAs having a disproportionate risk of CKD. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12933-018-0712-1) contains supplementary material, which is available to authorized users.