Prolonged QT interval is linked to all-cause and cardiac mortality in chronic peritoneal dialysis patients

Abstract

Aim: Prolonged QT interval is related to changes of electrolytes in haemodialysis (HD) and is associated with all-cause mortality in HD patients. It is unknown if prolonged QT interval is associated with all-cause mortality in peritoneal dialysis (PD) patients as the electrolytes were relatively stable in PD. We therefore investigated the association of prolonged QT interval and all-cause mortality in chronic PD patients.

Methods: The QT intervals were measured in 2003 and all patients were followed to December 2012. A prolonged QT interval was defined as a QT interval > 450 ms. The association of prolonged QT interval with all-cause and cardiac-specific mortality was analyzed using Cox regression and Kaplan-Meier analysis.

Results: Of 306 patients, 196 (64%) patients had prolonged QT interval. The incidence density rate was 9.7 per 100 persons-years for all-cause mortality and 5.6 for cardiac specific mortality in patients with prolonged QT interval. Prolonged QT interval was associated with all-cause mortality with a hazard ratio (HR) of 1.59 (95% confidence interval (CI): 1.06-2.39, P = 0.03] and cardiac mortality (HR: 1.66, 95% CI: 1.00-2.78, P = 0.05) with adjustments for age, gender, diabetes, and vintage of dialysis. Longer QT interval (>500 ms, 450-500 ms, and < 450 ms) was significantly associated with a worse overall survival (P = 0.03, log-rank test) and cardiac mortality free survival (P = 0.05, log-rank test).

Conclusions: Prolonged QT interval was associated with all-cause and cardiac mortality in patients on peritoneal dialysis. The association is independent of patient's age and diabetes.

Keywords: QT interval; cardiac mortality; mortality; peritoneal dialysis.