Association of Peritonitis With Cardiovascular Mortality Over Time in the Peritoneal Dialysis Population: An Australia and New Zealand Dialysis and Transplant Registry Study

INTRODUCTION: Though peritonitis is associated with increased mortality in patients receiving peritoneal dialysis (PD), its association with cardiovascular mortality remains uncertain. METHODS: The study participants included adult patients (≥18 years old) commencing PD in Australia (from October 2003 to December 2019) using the Australia and New Zealand Dialysis and Transplant (ANZDATA) registry. Association between peritonitis and cardiovascular mortality was evaluated using Cox proportional hazards analysis and competing risks analysis. Associations between peritonitis rates between different eras and cardiovascular mortality were also compared using Jointpoint regression model to determine the time point when a significant change in peritonitis trend occurred to define the era for cardiovascular mortality. Subgroup analysis dividing the groups into 0, 1 and ≥2 episodes of peritonitis and sensitivity analysis censoring at 90 days post-transfer to hemodialysis (HD) were performed. RESULTS: The study included 9699 incident PD patients. The overall peritonitis rate was 0.37 episodes per patient-year and declined by 4.7% (95% confidence interval [CI] 3.6–5.8%) during the study period. Peritonitis was associated with increased cardiovascular mortality risk (subdistribution hazard ratio [SHR] 1.53, 95% CI 1.39–1.69, P < 0.001) with increasing peritonitis episodes associated with higher risk (1 episode of peritonitis SHR 1.41, 95%CI 1.24–1.61; ≥2 episodes of peritonitis SHR 1.69, 95% CI 1.47–1.93, P < 0.001). Patients who commenced PD between 2012 and 2019 had a lower risk of cardiovascular mortality (SHR 0.60, 95% CI 0.50–0.72, P < 0.001), compared to patients who commenced between 2003 and 2011. Results were consistent in the sensitivity analysis. CONCLUSION: Peritonitis is independently associated with an increased risk of cardiovascular mortality, and the association is episode-dependent. Prevention and adequate treatment of PD peritonitis may improve cardiovascular outcomes among patients receiving PD.