Daily fluid intake and outcomes in kidney recipients: post hoc analysis from the randomized ABCAN trial.

Generous and even excessive fluid intake is routinely recommended to kidney transplant recipients despite minimal evidence to support this practice. We hypothesized that increased fluid intake, ascertained by 24-hour urine volume output, may adversely affect graft outcomes as it would impose an extra workload on a limited number of nephrons. Kidney transplant recipients who were randomized to losartan vs. placebo in the ABCAN trial (n=153) underwent baseline, five-year biopsies and annual iothalamate GFR assessment. Recipients with higher urine volume at randomization had higher urinary sodium and also higher urinary protein. The proportion using diuretics or CNI based regimens were similar across urinary volume tertiles. The highest urinary volume tertile (>2.56 L/day) did not predict the development of interstitial volume doubling or ESRD from IF/TA (OR=3.52, 95% CI 0.4, 38.15, p=0.26), interstitial volume doubling or all-cause ESRD (OR=7.04, 95% CI 0.66, 74.87, p=0.10), and was not associated with the conventional endpoint of doubling serum creatinine, all cause ESRD, or death (OR=0.89, 95% CI 0.21, 3.71, p=0.87). These results suggest that the current practice of liberal fluid intake may not be beneficial in low risk and mostly Caucasian transplant recipients.