Circulating inflammatory markers and the risk of vascular complications and mortality in people with type 2 diabetes and cardiovascular disease or risk factors: the advance study

C-reactive protein (CRP), fibrinogen, and interleukin-6 (IL-6) are associated with cardiovascular disease (CVD) and death in general populations. However, studies of these factors in type 2 diabetes are limited. We studied their associations with the risk of major macrovascular events, microvascular complications, and mortality in patients with type 2 diabetes who participated in the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation (ADVANCE) Study. Plasma CRP, fibrinogen, and IL-6 levels were determined in a case-cohort study (n = 3,865) nested within the 11,140 men and women with type 2 diabetes and baseline CVD or risk factors in the ADVANCE Study. All three biomarkers of inflammation were associated with an increased risk of macrovascular events and death in analyses adjusted for age, sex, and treatment groups. After further adjustment, only IL-6 was an independent predictor of macrovascular events (hazard ratio per SD increase 1.37 [95% CI 1.24-1.51]) and death (1.35 [1.23-1.49]). IL-6 significantly improved the prediction of macrovascular events and death. After adjustment, none of the markers predicted microvascular complications. We conclude that IL-6 levels, but not CRP or fibrinogen levels, add significantly to the prediction of macrovascular events and mortality in individuals with type 2 diabetes who have baseline CVD or risk factors.