Urea kinetics and clinical features of long-term continuous ambulatory peritoneal dialysis patients

The purpose of this study was to assess urea kinetic modeling (UKM) as a marker for adequate dialysis in continuous ambulatory peritoneal dialysis (CAPD) patients. UKM was conducted on 19 anuric patients on CAPD for more than 2 years. Serum beta 2-microglobulin (beta 2M) was also measured as a marker of large molecular weight substances. Patient clinical conditions were evaluated by the doctors and patients as well. The patients were thus asked to complete a questionnaire on uremic symptoms and daily activities. A comparison was made in urea kinetics and biochemical parameters based on clinical assessment scores. Patient and doctor scores showed a close correlation (r = 0.69) and were correlated to days of hospitalization. The peritonitis rate was significantly higher in the "not doing well" group. No correlation could be found between indexes of UKM or beta 2M plasma level and clinical assessment scores. A significant correlation was noted between serum albumin concentration and doctor scores (r = 0.52). It was thus concluded that UKM was not a good indicator of the adequacy of dialysis for CAPD, but serum albumin was. However, clinical symptoms and signs are more important than biochemical parameters for assessing adequacy.