AimProlonged 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. MethodsThe QT intervals were measured in 2003 and all patients were followed to December 2012. A prolonged QT interval was defined as a QT interval>450ms. The association of prolonged QT interval with all-cause and cardiac-specific mortality was analyzed using Cox regression and Kaplan-Meier analysis. ResultsOf 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 (>500ms, 450-500ms, and<450ms) 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). ConclusionsProlonged 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.