Effect of Duration of Chronic Peritoneal Dialysis Therapy on the Development of Peritonitis

Abstract

Long-term chronic peritoneal dialysis (CPD) therapy has been associated with alterations in peritoneal membrane structure and peritoneal macrophage function. We thus reviewed our experience with the development of peritonitis among patients maintained on CPD therapy for various time periods to determine if the spectrum of organisms, rates of peritonitis, and outcome changed with the duration of CPD therapy. Patients maintained on CPD therapy in our out-patient unit in New Haven, Connecticut. Retrospective review of the charts of patients maintained on CPD therapy (HomeChoice Cycler or Ultrabag, Baxter, McGaw Park, IL, U.S.A.) between 1 January 1997 and 31 March 1998. These patients were divided into three groups: group 1, patients maintained on CPD therapy < or = 12 months; group 2, patients maintained on CPD therapy for 13-36 months; and group 3, patients maintained on CPD therapy for > or = 37 months. The study included 256 patients: 101 patients in group 1, 110 patients in group 2, and 45 patients in group 3. All groups of patients were similar in age. There were significantly fewer Caucasians and fewer males in group 3 in comparison to groups 1 and 2. The incidence of diabetes mellitus, coronary artery disease, and peripheral vascular disease was significantly lower among patients in group 3 in comparison to groups 1 and 2. There were 155 episodes of peritonitis during the study period for an overall rate of 1 episode in 18.7 patient-months. The overall, gram-positive, and gram-negative rates of peritonitis were not significantly different among the patients in groups 1, 2, and 3. There were more episodes of Staphylococcus aureus peritonitis among patients in group 3 in comparison to group 2 (1 episode in 59.6 vs 1 episode in 280.2 patient-months, respectively). Two weeks after the development of peritonitis, 94.6% of the patients in group 3 continued CPD therapy, while 79.4% of the patients in group 1 continued CPD therapy (p < 0.05). No patient in group 3 transferred to hemodialysis, while 10.3% and 8.2% of the patients in groups 1 and 2 transferred to hemodialysis (p < 0.05). The death rate 2 weeks after the onset of peritonitis was 10.3%, 9.8%, and 5.4% in groups 1, 2, and 3, respectively (p = NS). Despite the immunological and morphological changes that occur in the peritoneal cavity with increased time on CPD therapy, there was no difference in the overall, gram-positive, or gram-negative rates of peritonitis for patients maintained on CPD therapy for various time periods. Patients in group 3 continued CPD therapy more often than did patients in group 1. Patients in group 3 transferred to hemodialysis less often than did the remaining patients in the study period. The incidence of death was not significantly different for the three groups of patients.