Analysis of Extracellular Fluid Volume in Peritoneal Dialysis Patients before and after Kidney Transplantation

To examine the relationship of extracellular fluid (ECF) volume and osmotic excess with treatment modality, we retrospectively analyzed spontaneous body weight loss and osmotic excretion versus true body weight after kidney transplantation in peritoneal dialysis (PD) patients and preemptive transplant recipients compared with hemodialysis (HD) patients. We also examined maximum bladder volume in other transplant recipients on PD.

From 2005 to 2011, 42 PD patients underwent kidney transplantation at our institution. Patients aged <12 years and cadaveric transplantations were excluded; we enrolled 27 PD patients (PD group; age 35.7 ± 14.4 years at transplantation; dialysis duration 36.5 ± 31.2 months) and 14 adult preemptive kidney transplant patients (preemptive group; age 31.7 ± 15.7 years; estimated glomerular filtration rate 8.26 ± 1.8 mL/min/1.73 m2 at transplantation). From 2005 to 2006, 29 adult living-related donor kidney transplant recipients on HD support (HD group) were enrolled as controls (age 36.4 ± 11.3 years; dialysis duration 37.5 ± 55.2 months).

Percentage body weight loss at 1 month after transplantation was 5% from ideal body weight for the PD group (51.2 ± 14.3 to 48.6 ± 13.0 kg, p = 0.002), 5.1% for the preemptive group (56.7 ± 17.4 to 53.8 ± 16.5 kg, p = 0.0005), and 1% for the HD group (52.9 ± 12.4 to 52.1 ± 12.5 kg, p = 0.079); post-transplantation 24-h osmotic excretion was greater in the PD and preemptive groups (387.3 ± 175.7 mOsm) groups than in HD (250 ± 124 mOsm; p = 0.006. Another 69 adult living-related donor kidney transplant recipients (PD and HD support) with dialysis duration ≤5 years were examined. Mean dialysis duration differed in the HD (17.5 ± 13.1 months) and PD (29.6 ± 20.4 months, p = 0.015) groups; mean urine volume and maximum desire to void (MDV) were similar.

ECF volume and osmotic excess occurred in the PD and preemptive groups compared with the HD group pre-transplantation. Although PD maintains MDV and residual and total urine volume, ECF volume and osmotic excess should be monitored before transplant; pre-transplant HD support should always be considered in PD and preemptive transplant patients.