Peritonitis Before Kidney Transplant Linked to Worse Outcomes

Key Takeaways

• In kidney transplant recipients in Australia and New Zealand who started kidney replacement therapy with peritoneal dialysis, nearly one-third had pretransplant peritonitis, which was associated with higher posttransplant risks of graft failure and death.
• Overall pretransplant peritonitis history was not significantly associated with acute rejection after multivariable adjustment.
• Recent peritonitis showed the most adverse overall pattern, but the authors cautioned that, because multiple outcomes were evaluated, individual findings should be interpreted within the broader consistency of the results.
• Episodes that led to transfer to hemodialysis were associated with higher graft failure risk, and both single and multiple episodes tracked with graft failure and mortality without a clear dose-response gradient.

Peritoneal dialysis-related peritonitis is a common complication in kidney transplant candidates treated with peritoneal dialysis, but whether its timing, burden, or severity marks a distinct posttransplant risk profile has remained uncertain. Persistent inflammation, treatment disruption, and broader clinical vulnerability could plausibly carry into the transplant period, yet the downstream significance of those features has been unclear. Kidney transplant recipients in Australia and New Zealand therefore provided a large routine-care population in which to examine whether pretransplant peritonitis history was associated with outcomes after transplant.

The JAMA Network Open ANZDATA cohort study of PD-related peritonitis and kidney transplant outcomes used the Australia and New Zealand Dialysis and Transplant Registry (ANZDATA) to study adults aged 18 years or older who initiated peritoneal dialysis (PD) as their first kidney replacement therapy (KRT) and later underwent kidney transplant from 2006 through 2024. The cohort included 4,957 patients with median follow-up of 6.0 years (interquartile range [IQR] 2.6-9.3) in Australia and New Zealand practice settings. Exposure was any pretransplant PD-related peritonitis, with secondary categories based on timing before transplant, number of episodes, and whether an episode led to transfer to hemodialysis. Prespecified outcomes were biopsy-proven acute rejection, death-censored graft failure, and all-cause mortality, analyzed with multivariable Cox models and checked in weighted and Fine-Gray sensitivity analyses.

Pretransplant peritonitis occurred in 1,483 patients (30%). After multivariable adjustment, any peritonitis history was associated with higher risk of death-censored graft failure, with an adjusted hazard ratio (aHR) of 1.55 (95% confidence interval [CI] 1.26-1.90), and higher all-cause mortality, aHR 1.25 (95% CI 1.06-1.48), but not with acute rejection overall. The strongest association appeared when peritonitis occurred within 6 months before transplant, with graft failure aHR 2.28 (95% CI 1.73-3.00); that recent-peritonitis subgroup also had significantly higher acute rejection and mortality risk. Peritonitis severe enough to require transfer to hemodialysis was also associated with higher graft failure risk, and weighted and competing-risk analyses were broadly consistent.

Because the analysis was observational, residual confounding and indication bias could not be excluded. Key immunologic variables, including panel reactive antibody and human leukocyte antigen mismatch, were unavailable, and organism-specific effects could not be assessed in the registry. Restriction to patients who ultimately underwent transplant may also have introduced survivor bias. The authors noted that possible pathways such as inflammation, malnutrition, adherence, or broader vulnerability were not directly measured, so the findings do not establish a single mechanism.

The authors concluded that pretransplant PD-related peritonitis, especially when recent, was associated with worse posttransplant outcomes in this transplanted PD population. They called for further studies with more detailed clinical and adherence data to clarify the pathways behind the association.

Clinician Questions

Which kidney transplant recipients were included in the ANZDATA peritonitis analysis?

The analysis included adults aged 18 years or older with kidney failure who initiated PD as their initial KRT and later underwent kidney transplant in Australia or New Zealand between 2006 and 2024. Follow-up ran from transplant until death, loss to follow-up, or December 31, 2024, defining the transplanted PD population to which the findings apply.

How was pretransplant peritonitis categorized before kidney transplant in this cohort?

Pretransplant exposure was defined as any history of PD-related peritonitis before kidney transplant, then categorized by timing relative to transplant as more than 6 months or 6 months or less, by episode burden as 1 or multiple episodes, and by severity according to whether a peritonitis episode led to transfer to hemodialysis.

What did the sensitivity analyses show for PD-related peritonitis and kidney transplant outcomes?

Weighted Cox and Fine-Gray analyses were broadly consistent with the primary findings. Graft failure remained associated with prior peritonitis after excluding kidney transplant recipients with any hemodialysis transfer, and excluding acute rejection events within 7 days after transplant still did not show a significant overall association between peritonitis history and acute rejection.