Background: The impact of peritoneal dialysis-associated peritonitis (PD peritonitis) on long-term outcomes is uncertain. This nationwide retrospective study was conducted in Taiwan to understand the incidence, risk factors and long-term outcomes of PD peritonitis.
Methods: A total of 11,202 incident adult peritoneal dialysis (PD) patients from 2000 to 2010 were collected from a Longitudinal Health Insurance Database and followed up until the end of 2011. Definition of peritonitis, the primary outcome, simultaneously met the diagnosis of peritonitis (International Classification of Diseases, Ninth Revision, Clinical Modification 567) and antibiotic use. Secondary outcomes included the impact of peritonitis on PD discontinuation and survival. Cox proportional hazards models with and without time-dependent variables were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs).
Results: There were 7634 peritonitis episodes in 4245 patients during the follow-up period. The overall incidence of peritonitis was 0.18 episodes per patient-year. Peritonitis-associated risk factors included older age, female gender, chronic heart failure, cerebrovascular disease, liver cirrhosis and lower monthly income. In an adjusted Cox hazard proportional regression with the time-dependent model, peritonitis patients had a higher risk of PD discontinuation (HR 2.71, 95% CI 2.52-2.92) and mortality (HR 1.68, 95% CI 1.57-1.81) compared to patients without peritonitis. The adjusted HRs for mortality increased with each prior episode: one episode, two episodes and more than two episodes (all p < 0.05). The adjusted HRs for PD discontinuation also increased with the frequency of peritonitis. These negative effects were greatest during the first year and persisted significantly after 5 years. In a sensitivity analysis in which peritonitis within 30 days of death or PD discontinuation was excluded, peritonitis patients still had significantly increased risk of PD discontinuation and mortality compared to patients without peritonitis.
Conclusions: Although peritonitis incidence was low, our findings reveal that peritonitis carried acute and long-term sequelae of higher PD discontinuation and lower patient survival.
Keywords: Mortality; PD discontinuation; peritoneal dialysis; peritonitis; time-dependent model.