Peritoneal dialysis clearance can replace residual renal function

There is controversy whether increasing peritoneal clearance effectively substitutes for declining residual renal function. We studied the impact of renal and peritoneal clearances on outcome, controlling for comorbidity.

Registry database.

Four dialysis centers.

Incident peritoneal dialysis patients.

Data were collected prospectively on 90 incident patients between 1991 and 1999. At the end of their first year on peritoneal dialysis, patients were divided into groups based on the first year's clearance results: group 1 (n = 62) had weekly Kt/W greater than or equal to 2.0 and creatinine clearance (CCr/1.73 m2) greater than or equal to 60 L throughout the first year; group 2 (n = 28) fell below these targets due to loss of residual renal function and then reached targets due to prescription change.

Patient and technique survival.

Both groups were similar in baseline characteristics except age (57 years vs 49 years, p = 0.02) and initial albumin (34.4 g/L vs 37.5 g/L, p = 0.001). One-year patient survival after grouping was similar in both groups (86.3% vs 80.9%, p = 0.72). Cox proportional hazard model, controlling for comorbidity, did not show "group" to be a significant predictor of outcome (p = 0.96). One-year technique survival after grouping was similar in both groups (77.3% vs 83.2%, log rank p = 0.89). For technique failure, Cox proportional hazard model showed peritonitis (p = 0.004) to be the only significant predictor of worse outcome.

Peritoneal dialysis patients with improved clearances due to prescription changes had survival comparable to patients who never fell below target. This suggests that loss of residual renal function may be replaced by increasing peritoneal dialysis clearance. A large multicenter trial to study this important question further is needed.