Daily peritoneal ultrafiltration predicts patient and technique survival in anuric peritoneal dialysis patients

Maintenance dialysis therapy is the only way to remove excess fluid in patients with anuric end-stage renal disease. The optimal ultrafiltration (UF) volume in patients on peritoneal dialysis (PD) remains controversial.

We retrospectively analysed a cohort of 86 prevalent anuric PD patients followed up for a median of 25.3 months (range, 6 to 54 months). Clinical and PD parameters were recorded yearly. Kaplan-Meier analysis and Cox proportional hazards models were used to identify risk factors of mortality and technique failure in patients with a UF >/=1 L/24 h or <1 L/24 h.

When compared to those with a UF <1 L/24 h, patients with a UF >/=1 L/24 h had significantly higher haemoglobin levels (101.9 +/- 20.5 vs 89.3 +/- 20.2 g/L, P < 0.05) and tended to be younger (55.0 +/- 12.5 vs 60.6 +/- 16.1 years, P = 0.10). Also, while Kt/V and CCr were stable over time, UF decreased significantly over the study period (baseline, 1205.5 +/- 327.3 ml/24 h vs after 3 years, 870.6 +/- 439.8 ml/24 h; P < 0.001). Using Kaplan-Meier analysis, patients with baseline UF <1 L/24 h had significantly worse outcome (survival, 27.2 +/- 3.9 vs 42.4 +/- 1.9 months; P < 0.001). In multivariate Cox regression analysis, age, time-dependent UF volume and serum albumin were independent predictors of mortality, while UF independently predicted technique failure.

The present study demonstrates a strong predictive value of daily peritoneal UF for both technique and patient survival in prevalent anuric PD patients. Identifying markers of satisfactory fluid status, as well as optimizing therapy to meet UF goals, remains an important clinical target.