QT prolongation in patients with Type 2 diabetes and microalbuminuria.

The link between microalbuminuria and premature death in Type 2 diabetes is not fully explained by conventional cardiovascular risk factors. We aimed to determine if QT prolongation and/or dispersion are linked to microalbuminuria in patients with Type 2 diabetes and to investigate their associations with other risk factors. We have studied asymptomatic patients with Type 2 diabetes with no clinical evidence of coronary disease (43 with microalbuminuria matched with 43 normoalbuminuric patients). Rate-corrected maximum QT interval (QT(c) max) was greater in the microalbuminuric group [mean (SD): 450 (23) vs 440 (20) ms(1/2), p = 0.046] as was the proportion of patients with QT(c) max > 440 ms (67 % vs 38 %, p = 0.01). Rate-corrected QT dispersion (QT(cd)) was similar in the two groups [57 (21) vs 53 (23) ms(1/2), p = 0.41]. Linear regression analysis showed that QT(c) max and/or QT(cd) were not strongly linked to albumin excretion rate but more strongly to factors associated with microalbuminuria such as blood pressure and factor XIIa. Our findings support the hypothesis that QT prolongation and microalbuminuria have common determinants in Type 2 diabetes. QT prolongation may contribute to the increased mortality observed in microalbuminuric subjects with Type 2 diabetes.