Association Between Peritoneal Dialysis-Associated Peritonitis and the Risk of All-Cause Mortality and Cardiovascular Death: A Time-Matched Retrospective Cohort Study

Background/Objectives: Although peritoneal dialysis (PD) practices have improved over the past decades, limited evidence exists on all-cause mortality and cardiovascular death following PD-associated peritonitis. This study aimed to investigate the association between PD-associated peritonitis and the risk of all-cause mortality and cardiovascular death. Methods: This multicenter, retrospective cohort study included adult patients who newly initiated PD between 1 January 2006 and 31 December 2020, with follow-up through 30 September 2022. Patients were matched 1:1 by time from PD initiation to index date (the occurrence date of PD-associated peritonitis for the exposure group and the corresponding matched time on PD for the non-exposure group [individuals without any peritonitis event]), age, and sex. Multivariable Cox proportional hazards models with shared frailty correction and competing risk models were used to estimate hazard ratio (HR) and subdistribution hazard ratio (SHR), respectively. Subgroup analyses were conducted by age, sex, PD modality, and comorbid conditions. Results: The cohort included 1510 matched pairs (total sample, 3020; mean age [SD], 58.6 [14.2] years; 1618 males [53.6%]), with a median follow-up of 5.6 years. After adjusting for sociodemographic, PD, and clinical characteristics and laboratory profiles, patients with any PD-associated peritonitis episode had significantly higher risk of all-cause mortality (HR, 2.17 [1.78–2.66], p < 0.001; SHR, 2.00 [1.74–2.29], p < 0.001) and cardiovascular death (HR, 2.90 [2.05–4.59], p < 0.001; SHR, 2.25 [1.66–3.05], p < 0.001) compared to those without PD-associated peritonitis. Subgroup analyses revealed no significant interactions (all p values for interaction > 0.05). Conclusions: PD-associated peritonitis was independently associated with substantially increased risk of all-cause and cardiovascular mortality among patients undergoing PD. These findings support the need for targeted interventions and clinical strategies aimed at reducing adverse outcomes following PD-associated peritonitis.