The value of QT interval dispersion for identification of total mortality risk in non-insulin-dependent diabetes mellitus

Abstract

Objectives. To delineate different risk markers including the difference between the maximum and the minimum length of the QT interval in ECG corrected for heart rate (QTc dispersion) as predictors of total, cardiac and cerebrovascular mortality in NIDDM patients. Design. Case-control, follow-up study until death or for a period of 15 to 16 years. Setting. Tertiary care centre, University Hospital of Dusseldorf, Germany. Subjects. 216 unselected consecutive NIDDM patients. Main outcome measures. Total, cardiac, and cerebrovascular mortality. Results. During the follow-up 158 (73%) patients died. In the Cox proportional hazards model QTc dispersion was the most important independent predictor of total mortality (risk ratio (RR) 3.3; difference for RR: 0.05 s(1/2); P = 0.001). Additional independent risk markers were age, male sex, systolic blood pressure, diabetic retinopathy, micro- or macroproteinuria, total serum cholesterol and HDL cholesterol. The QTc dispersion was also an independent predictor of cardiac and cerebrovascular mortality. Conclusions. The results of this long-term follow- up study indicate that QT dispersion in a routine ECG is a useful marker to identify NIDDM patients with a high mortality risk.