QTc Interval Prolongation Is a Predictor of Future Strokes in Patients With Type 2 Diabetes Mellitus

Abstract

Background and Purpose— QTc interval prolongation is a predictor of cardiovascular morbidity and mortality in general populations and in patients with diabetes. The aim of this study was to investigate the predictors of stroke in patients with type 2 diabetes, with particular emphasis on the independent role of QT interval parameters. Methods— We carried out a long-term follow-up study with 471 type 2 diabetics. Several clinical, laboratory, ECG, and echocardiographic variables were recorded at baseline. Predictive factors for stroke were evaluated by Kaplan-Meier estimation of survival curves and by univariate and multivariate Cox survival analyses. Results— After a median follow-up of 57 months (range, 2 to 84 months), 40 incident strokes were observed. QTc interval prolongation (≥470 ms 1/2 ) was an independent predictor of stroke, with adjusted hazard ratios ranging from 2.2 to 2.9 (95% confidence intervals, 1.1 to 6.0). Other independent factors associated with stroke were older age; the presence of cerebrovascular disease at baseline; increased 24-hour proteinuria, serum triglycerides, and left ventricular mass; and decreased high-density lipoprotein cholesterol. Excluding patients with previous cerebrovascular disease from the analysis did not change the results significantly. Conclusions— QTc interval prolongation is a predictor of future stroke in patients with type 2 diabetes. Intervention studies are needed to assess whether this factor could be modified.