Prolonged QT interval is associated with cardiac arrhythmias and sudden death. The present study determined the prevalence of prolonged QT interval and QT dispersion and defined their clinical and metabolic predictors in patients with type 2 diabetes.
Cross-sectional study included 501 patients with type 2 diabetes. A standard 12-lead electrocardiogram was recorded. QT corrected for heart rate (QTc) >440 ms and QT dispersion (QTd) >80 ms were considered abnormally prolonged. QTc ≥ 500 ms was considered a high-risk QTc prolongation. Demographic, clinical and laboratory data were collected. Independent risk factors for prolonged QTc and QTd were assessed using logistic regression analysis.
Prevalence of QTc > 440 ms and QTd > 80 ms were 44.1 and 3.6 %, respectively. Prevalence of high-risk QTc (≥500 ms) was 2 % only. Independent risk factors for QTc prolongation >440 ms were mean blood glucose ( β = 2.192, p < 0.001), treatment with sulphonylurea ( β = 5.198, p = 0.027), female gender ( β = 8.844, p < 0.001), and coronary heart disease ( β = 8.636, p = 0.001). Independent risk factors for QTc ≥ 500 ms were coronary heart disease ( β = 4.134, p < 0.001) and mean blood glucose level ( β = 1.735, p < 0.001). The independent risk factor for prolonged QTd was only coronary heart disease ( β = 5.354, p < 0.001).