Peritoneal functional parameters after five years on continuous ambulatory peritoneal dialysis (CAPD): the effect of late peritonitis.

Functional stability of the peritoneum is essential for patients on long-term continuous ambulatory peritoneal dialysis (CAPD) treatment. Sixteen patients on CAPD treatment for at least 4 years were studied. Their mean age was 47 +/- 15 years, 5 were males, and none were diabetic. Residual creatinine clearance at the beginning was 2.1 +/- 2.6 mL/min. Once yearly since starting CAPD, we have evaluated their peritoneal ultrafiltration (UF) and diffusion capacities by calculating the peritoneal mass transfer coefficient (MTC, mL/min) for urea and creatinine. Patients were categorized so that we could distinguish the effect of peritonitis, betablockers, and hypertension. For all patients the average initial and final MTCs and UF values were not different. Early episodes of peritonitis (those occurring less than 36 months after starting CAPD) did not influence long-term function. However, late peritonitis (occurring greater than 36 months since initiation) induced a decrease in urea-MTC (22.3 +/- 6 to 15.8 +/- 3.9, p less than 0.05), creatinine-MTC (9.4 +/- 3.1 to 7.4 +/- 2.5, p less than 0.05), and a corresponding increase in UF (1.25 +/- 0.4 to 1.4 +/- 0.3, mL/min, p less than 0.05). Age, sex, betablockers and hypertension did not influence the peritoneal parameters followed. After 5 years on CAPD, functional stability of the peritoneum is evident, except for patients who suffer late episodes of peritonitis. We speculate that the peritoneum in patients who have been on long-term CAPD are more susceptible to injuries, such as peritonitis, and that this results in functional deterioration.