The Effect of Small Solute Clearances on Survival of Anuric Peritoneal Dialysis Patients

Abstract

Objective Primarily, to determine whether peritoneal small solute clearance is related to patient and technique survival among anuric peritoneal dialysis [continuous ambulatory (CAPD) and automated peritoneal dialysis (APD)] patients. A secondary goal was to describe the ability to attain Dialysis Outcomes Quality Initiative (DOQI) targets among anuric patients on peritoneal dialysis. Design Retrospective cohort study via chart reviews. Setting Peritoneal Dialysis Unit of Toronto Hospital (Western Division). Patients The study included 122 CAPD and APD patients between January 1992 and September 1997, with 24-hour urine volume less than 100 mL, or renal creatinine clearance (CCr) less than 1 mL/minute. Adequacy data were available for 115 patients. Outcome Measures Mortality and technique failure (TF). Regression analysis was used to estimate the mortality and TF rate ratios (RR) for peritoneal Kt/V urea (pKt/V) and pCCr, adjusting for age, gender, diabetes, months of follow-up prior to anuria, albumin, transport status, coronary artery disease, cardiovascular disease, and peripheral vascular disease. Results Fifty seven per cent (51/89) of patients on CAPD and 81% (21/26) on APD had a weekly pKt/V ≥ 2 and ≥ 2.2, respectively (DOQI targets); whereas only 35% on CAPD (31/89) and 35% (9/26) on APD had a weekly pCCr ≥ 60 L/1.73 m2 and 66 L/1.73 m2, respectively. Median follow-up times among patients were 16.5 and 19.5 months pre- and postanuria, respectively. Patients with pKt/V ≥ 1.85 experienced a strong decrease in patient mortality (RR = 0.54, p = 0.10); the effect was less pronounced for pCCr ≥ 50 L/1.73 m2 (RR = 0.63, p = 0.25). No relationship was observed between pKt/V or pCCr and TF. Conclusion Mortality was noticeably less frequent among patients with a pKt/V ≥ 1.85 compared with those with a Kt/V < 1.85 ( p = 0.10). Given the magnitude of the association, the failure to observe statistical significance relates to the size of the patient cohort. Our results imply that it is, in fact, possible to achieve DOQI targets among anuric patients on peritoneal dialysis.