Incidence rates and predictors of microvascular and macrovascular complications in patients with type 2 diabetes: Results from the longitudinal global discover study.

Background: Micro- and macrovascular complications are a major cause of morbidity and mortality in people with type 2 diabetes (T2D). We sought to understand the global incidence rates and predictors of these complications.

Methods: We examined the incidence of vascular complications over 3 years of follow-up in the DISCOVER study-a global, observational study of people with T2D initiating second-line glucose-lowering therapy. Hierarchical Cox proportional hazards regression models examined factors associated with development of micro- and macrovascular complications during follow-up.

Results: Among 11,357 people with T2D from 33 countries (mean age 56.9 ± 11.7 years, T2D duration 5.7 ± 5.1 years, HbA1c 8.4 ± 1.7%), 19.0% had a microvascular complication at enrolment (most commonly neuropathy), and 13.2% had a macrovascular complication (most commonly coronary disease). Over 3 years of follow-up, 16.0% developed an incident microvascular complication, and 6.6% had an incident macrovascular complication. At the end of 3 years of follow-up, 31.5% of patients had at least one microvascular complication, and 16.6% had at least one macrovascular complication. Higher HbA1c and smoking were associated with greater risk of both incident micro- and macrovascular complications. Known macrovascular complications at baseline was the strongest predictor for development of new microvascular complications (HR 1.40, 95% CI 1.21 -1.61) and new macrovascular complications (HR 3.39, 95% CI 2.84 -4.06).

Conclusions: In this global study, both the prevalence and 3-year incidence of vascular complications were high in patients with relatively short T2D duration, highlighting the need for early risk-factor modification.