The importance of overhydration in determining peritoneal dialysis technique failure and patient survival in anuric patients.

PURPOSE: Loss of residual renal function (RRF) is associated with an increased risk for peritoneal dialysis (PD) technique failure and patient death. We wished to determine which factors were associated with PD technique failure and patient mortality once urine output had fallen to <100 mL/day.

METHODS: We followed 183 PD patients who lost RRF and who had measurements taken at that time of PD small solute clearances, ultrafiltration volume, PD transport status and multiple frequency bioelectrical impedance assessments (MFBIA) of extracellular water (ECW).

RESULTS: 119 (65%) patients had PD technique failure or died during a median follow-up of 20.8 (10.5-36) months. This group had more men (58.8% vs. 31.9%, p = 0.011), and were older 57.9 ± 14.7 vs. 49.3 years (p = 0.002). These patients had a higher median C-reactive protein 5.5 [4.8-8.2] vs (5.0 [2-6] p = 0.013), and greater comorbidity (Davies grade 1 [0-1] vs. 0[0-1], p<0.001, and a higher ratio of ECW/TBW (0.45 ± 0.07 vs 0.42 ± 0.04, p<0.001). There were no differences in icodextrin usage, small solute clearance or ultrafiltration volumes. On multivariate Cox regression, ECW excess was significantly associated with PD technique failure and patient survival (β 1.09, p<0.001 and β1.17, p = 0.005), respectively.

CONCLUSIONS: Loss of urine output requires PD to provide both adequate solute clearances and volume control. We found that PD technique failure and patient death were associated with ECW excess. Prospective interventional studies are required to determine whether correction of volume status improves PD patient outcomes.