Prolonged QTc interval predicts mortality in patients with Type 1 diabetes mellitus
Version of Record online: 20 DEC 2001
Volume 18, Issue 3, pages 199–205, March 2001
How to Cite
Rossing, P., Breum, L., Major-Pedersen, A., Sato, A., Winding, H., Pietersen, A., Kastrup, J. and Parving, H. .-H. (2001), Prolonged QTc interval predicts mortality in patients with Type 1 diabetes mellitus. Diabetic Medicine, 18: 199–205. doi: 10.1046/j.1464-5491.2001.00446.x
- Issue online: 20 DEC 2001
- Version of Record online: 20 DEC 2001
- Accepted 4 November 2000
- diabetic nephropathy;
- QT dispersion;
- QTc interval
Aims To evaluate prolonged QTc interval and QT dispersion as predictors of all-cause and cardiovascular mortality after adjustment for well-established risk factors in Type 1 diabetic patients.
Methods From a cohort of all adult Type 1 diabetic patients, duration of diabetes ≥ 5 years, attending the clinic in 1984 and followed in an observational study for 10 years (n = 939), all subjects with resting baseline electrocardiograms were identified (n = 697, 360 males). The QT length was measured and corrected for heart rate (QTc). Maximal QTc length (QTc max) and QT dispersion were determined.
Results At baseline, 431 had normoalbuminuria (< 30 mg/24 h), 138 had microalbuminuria (30–299 mg/24 h) and 128 had macroalbuminuria (≥ 300 mg/24 h) of whom 66 (15%), 35 (25%) and 61 (48%) died during follow-up, respectively (26 (6%), 14 (10%), 21 (16%) from cardiovascular disease). QTc max. was 442 (1.2) ms (mean (sem)) for survivors and 457 (3.7) in patients who died (P < 0.001). In a Cox proportional hazards model including baseline values of putative risk factors, independent predictors of death were QTc max (P = 0.03), age (P < 0.001), presence of hypertension (P = 0.001), male sex (P < 0.001), log urinary albumin excretion (P < 0.001), smoking (P = 0.04), log serum-creatinine (P < 0.001), height (P < 0.001), low social class (P = 0.04), whereas QT dispersion, heart rate, and HbA1c were not included. In the subgroup with macroalbuminuria, but not for all patients, QTc max was an independent risk factor for cardiovascular mortality.
Conclusion QTc prolongation, but not increased QT dispersion, is an independent marker of increased mortality in patients with Type 1 diabetes mellitus.