Physiological Properties of the Peritoneum in an Adult Peritoneal Dialysis Population over a Three-Year Period

Objectives To describe the physiological properties of the peritoneal membrane in adult patients treated with peritoneal dialysis (PD) and to analyze the effects of patient characteristics and time.Design Observational study.Setting Department of Nephrology at the Sahlgrenska University Hospital.Method Peritoneal function was analyzed by the Personal Dialysis Capacity (PDC) test, based on the three-pore theory of capillary transport. The functional PDC variables are absorption, large-pore flow, and the area parameter (A 0 /Δx), which determines the diffusion of small solutes. The ultra-filtration (UF) coefficient is determined mainly by A 0 /Δx.Patients All patients ( n = 280) who had at least one PDC test done between September 1990 and August 1999.Results In 249 patients examined soon after start of PD, area was 19000 (SD 7100) cm 2 /cm/1.73 m 2 , large-pore flow 0.112 (SD 0.052) mL/min/1.73 m 2 , and the UF coefficient 0.071 (SD 0.032) mL/minute/mmHg/1.73 m 2 . Absorption was 1.54 (SD +2.64, –0.97) mL/min/1.73 m 2 . Large-pore flow was greater in patients with severe comorbidity than in patients with fewer comorbid conditions. Elderly patients had a lower UF coefficient than did younger patients ( p < 0.05). Repeated PDC tests were performed in 208 patients during a mean observation time of 18.4 months. There was a slight increase in the slope of the area-versus-time curve of 54 cm 2 /cm/1.73 m 2 per month (approximately 10% after 3 years, p < 0.01); all other parameters remained constant.Conclusion Patient characteristics have an impact on peritoneal performance already at the start of dialysis. Peritoneal function can remain essentially stable during medium long-term PD.