Peritoneal transport status correlates with morbidity but not longitudinalchange of nutritional status of continuous ambulatory peritoneal dialysis patients: A 2-year prospective study

Cross-sectional studies show that peritoneal transport status is associated with nutritional status and clinical outcome of continuous ambulatory peri toneal dialysis (CAPD) patients. High transporters often are assumed to hav e progressive malnutrition as a result of fluid overload and nutrient loss in dialysis effluent. There are few prospective data to confirm this assump tion, however. We studied 235 unselected CAPD patients to examine this poss ibility. There were 58 new cases and 177 prevalent cases. A standard perito neal equilibration test was performed at enrollment. All patients were foll owed for 2 years. Dialysis adequacy and nutritional assessment, including s erum albumin, protein nitrogen appearance, and lean body mass, were perform ed at 0, 12, and 24 months. Clinical outcome included hospitalization, actu arial patient survival, and technique survival, The mean age was 51.6 +/- 1 2.4 years, The mean 4-hour dialysate-to-plasma ratio of creatinine was 0.57 +/- 0.12 for all cases (0.60 +/- 0.12 for new cases). Patients were classi fied into three groups: high/high-average (H/HA) (63 cases), low-average (L A) (105 cases), and low (L) (67 cases) transporters, Baseline demographic d ata and total Kt/V were similar in all transport groups. There were weak co rrelations between 4-hour dialysate-to-plasma ratio of creatinine end basel ine serum albumin (r = -0.249, P < 0.001), protein nitrogen appearance(r = -0.190, P < 0.01), and percentage of lean body mass (r = -0.194, P < 0.01). The H/HA group was a specific but not a sensitive predictor of poor baseli ne nutritional status, There was no significant change in any nutritional i ndices after 2 years in new cases and prevalent cases, regardless of transp ort status. The differences in nutritional indices between groups remained unchanged during the study period. There was a significant difference in ho spitalization rate among peritoneal transport groups (median 12 versus 7 ve rsus 3 days per year for H/HA, LA, and L groups, Kruskal-Wallis test, P < 0 .05). The difference remained similar when new cases and prevalent cases we re analyzed separately. The L group had slightly better 2-year patient surv ival than the HMA group (90.2% versus 83.3%), but the result was not statis tically significant. We conclude that peritoneal transport status is not as sociated with longitudinal change of nutritional parameters, although trans port status is associated with short-term patient morbidity. Further study is needed to identify the mechanisms of poor clinical outcome in high perit oneal transporters. (C) 2001 by the National Kidney Foundation, Inc.