QT interval prolongation and mortality in type 1 diabetic patients - A 5-year cohort prospective study

OBJECTIVE - The aim of the study was to assess the relationship between QT interval prolongation and mortality in type 1 diabetic patients. RESEARCH DESIGN AND METHODS - Data on survival after 5 years were obtained from 316 of 379 patients (83.3%) who took part in a study on the prevalence of diabetic neuropathy and QT interval prolongation. RESULTS - Mortality at 5 years was 6.32%. Patients who survived were signif icantly younger (P = 0.04), had a shorter duration of diabetes (P = 0.01), had lower systolic (P = 0.004) and diastolic (P = 0.03) blood pressure leve ls, and had a shorter QT interval corrected for the previous cardiac cycle length (QTc) (P = 0.000005) than subjects who died. In univariate analysis, patients had a higher risk of dying if they had a prolonged QTc (odds rati o [OR] 20.14 [95% CI 5.7-70.8]) or if they were affected by autonomic neuro pathy (3.55 [1.4-8.9]). QTc prolongation was the only variable that showed a significant mortality OR in multivariate analysis (24.6 [6.51-92.85]; P = 0.000004). CONCLUSIONS - This is the first cohort-based prospective study indicating t hat QTc prolongation is predictive of increased mortality in type 1 diabeti c patients.