Glycemic control and the risk of multiple microvascular diabetic complications

Tight glycemic control in type 2 diabetes reduces risk of certain end-organ complications. However, among patients with one complication already, it is unknown whether tight glycemic control reduces the risk of subsequent complications in another organ. We sought to determine if glycemic control is associated with the risk of a second, distinct, end-organ diabetic complication. Subjects were a retrospective cohort of 250 patients with type 2 diabetes, at least one microvascular diabetic complication, and at least one hemoglobin A1c (HbA1c) measurement after that complication. Proportional hazard models estimated the relative hazard of developing another diabetic complication in a second organ system, as predicted by either (1) mean HbA1c level over the study period or (2) first HbA1c after the initial complication. Thirty-eight patients had a second complication; the average follow-up duration was 3.7 years. The mean HbA1c model showed an adjusted relative hazard of 1.25 (95% confidence interval [CI]=1.04, 1.51) per percentage-point elevation in mean HbA1c. The first HbA1c model showed an adjusted relative hazard of 1.23 (95% CI=1.08, 1.40) per percentage-point elevation in first HbA1c. Among these type 2 diabetes patients with an initial complication, tight glycemic control was associated with reduced risk of additional complications in other organs.