Continuous ambulatory peritoneal dialysis versus automated peritoneal dialysis and peritonitis in the short and very...

Peritonitis (P) is the most important infectious complication in peritoneal dialysis (PD), but disagreement remains about the impact of PD modality on the frequency of P episodes. We compared indices linked to P between patients on continuous ambulatory PD (CAPD) and those on automated PD (APD) in the short and very long term. The study included 9 prevalent and 72 incident patients on CAPD (twin-bag system) and 37 incident patients on APD from 4 August 1995 to 31 March 2011. Data were collected prospectively from our database. The cumulative P rate (CPR) by weighted Student t-test (p < 0.05) expressed as the probabilities of remaining free of a first P episode and remaining free of all P episodes were compared by the Kaplan-Meier method (log rank p < 0.05). The proportion of patients with P (PPP) per group (chi2 p < 0.05) and the relative risk (RR) of P were also calculated. The CAPD patients included 51 women and 30 men [mean age.: 50.2 +/- 14.21 years (range: 15-82 years); duration of treatment: 3579 patient-months (mean: 44.2 +/- 34.2 patient-months); P episodes: 111] had a CPR of 0.38 episodes (1 episode in 31.35 patient-months) and a P rate per year (PRY) in the range 0.08-0.89 episodes. The APD patients [23 women and 14 men; mean age: 53.62 +/- 13.61 years (range: 26-78 years); duration of treatment: 1718 patient-months (mean: 46.4-38.3 patient-months); P episodes: 46] had a CPR of 0.32 episodes (1 episode in 373 patient--months) and a PRY in the range 0-1.12 episodes. At 1, 3, 5, and 10 years respectively, a first P episode occurred in 73%, 36%, 23%, and 8% of CAPD and 72%, 59%, 35%, and 23% ofAPD patients (log-rank p = 0. 056; CPR: p = 0.01; PPP: chi2 p = 0.39), for a RR of 0.83 linked to CAPD compared with APD. A lower P frequency and a trend of less time to first P was observed for APD compared with CAPD. The CAPD patients did not show a higher risk of developing P than did the APD patients. For comparisons between the modalities, CPR is a reliable index in the very long term at risk. Depending on the size of the population and the time at risk, the PRYobtained on short follow-up could result in a misinterpretation of the performance of each treatment modality.