Peritoneal Dialysis–Related Peritonitis and Kidney Transplant Outcomes

Importance: Peritoneal dialysis (PD) is a common dialysis modality before kidney transplant. Peritonitis, a major complication of PD, may be associated with adverse posttransplant outcomes. Objective: To examine the association between history of peritonitis and outcomes among patients undergoing PD followed by kidney transplant. Design, Setting, and Participants: This is a retrospective cohort study of the Australia and New Zealand Dialysis and Transplant Registry. Patients who initiated PD as first kidney replacement therapy and underwent kidney transplant during 2006 to 2024 were included and followed-up from transplant until death, loss to follow-up, or December 31, 2024. Exposures: History of peritonitis. Main Outcomes and Measures: The primary outcomes were biopsy-proven acute rejection, death-censored graft failure, and all-cause mortality. Time-to-event outcomes were evaluated using multivariable Cox proportional hazard regression models. Results: A total of 4957 patients (median [IQR] age, 52 [42-61] years; 2912 male [59%]) were included, with a median (IQR) follow-up duration of 6.0 (2.6-9.3) years. Patients with peritonitis (1483 patients [30%]) were more likely to have obesity, have a higher comorbidity burden with a history of smoking, longer dialysis duration, and prior treatment with continuous ambulatory PD. Multivariable Cox regression analyses showed that peritonitis history was associated with shorter time to graft failure (adjusted hazard ratio [aHR], 1.55; 95% CI, 1.26-1.90) and death (aHR, 1.25; 95% CI, 1.06-1.48), but not with acute rejection (aHR, 1.09; 95% CI, 0.94-1.25). These findings were consistent across inverse probability-weighted Cox regression analyses and Fine-Gray competing risk models. Patients with recent peritonitis (≤6 months before transplant) had significantly higher risks of acute rejection (aHR, 1.52; 95% CI, 1.22-1.88), graft failure (aHR, 2.28; 95% CI, 1.73-3.00), and death (aHR, 1.37; 95% CI, 1.04-1.80), compared with those without peritonitis history. These associations were not consistently observed among patients with more remote peritonitis. Furthermore, peritonitis resulting in transfer to hemodialysis was associated with increased risk of graft failure (aHR, 1.99; 95% CI, 1.49-2.67; reference, no peritonitis), whereas a more modest increase was observed in cases not requiring hemodialysis transfer (aHR, 1.40; 95% CI, 1.11-1.76; reference, no peritonitis). Conclusions and Relevance: These findings suggest that a history of peritonitis is associated with increased risks of graft failure and death after kidney transplant and highlight the importance of comprehensive pretransplant assessment and longitudinal risk stratification.