Differences between Western and Asian type 2 diabetes patients in the incidence of vascular complications and mortality: A systematic review of randomized controlled trials on lowering blood glucose

Background: Differences exist between Western and Asian people with type 2 diabetes (T2D). The aim of the present systematic review was to determine whether there are differences in chronic diabetic vascular complications (CDVCs) and mortality between Western and Asian patients with T2D. Methods: Three databases (EMBASE, MEDLINE, and Cochrane library) were searched for publications from 1966 to March 2013 describing interventional randomized control trials (RCTs) targeting to lower blood glucose levels. The RCTs included had follow-up durations of at least 4 years as an endpoint or in their initial design, analyzed effects on mortality and/or CDVCs in T2D and compared differences in mortality and/or CDVCs among patients of different ethnicities. Results: Two studies, including 19 439 patients with advanced diabetes, were eligible for analysis. Patients were divided into those of Western (including Australia and New Zealand) and Asian ethnicities. The incidence of all-cause mortality, cardiovascular death, and major coronary events was significantly higher in Western than Asian patients, whereas the incidence of major cerebrovascular events, microvascular events (except for peripheral neuropathy), new or worsening nephropathy, and retinopathy was significantly lower in Western patients. There were no-between group differences in macrovascular events, including cardiovascular death, non-fatal myocardial infarction, and non-fatal stroke. Conclusions: There are differences in CDVCs and mortality rates between Western and Asian patients with advanced T2D, primarily due to ethnicity-specific factors (e.g. different genetic background, lifestyle). Knowledge of these disparities may allow more effective monitoring and management of individual patients based on ethnic differences.