Water intake, baseline biopsy, and graft function after living donor kidney transplantation

Increased water intake is recommended for kidney transplant recipients; however, its efficacy remains controversial. We hypothesized that pre-existing histological findings of the allograft might modulate the impact of water intake. We retrospectively analyzed 167 adults with living-donor kidney transplants (April 2011–May 2020; median observation period, 77 months) whose baseline biopsy data were available. We compared the chronic-change group (n = 38) with the control group (n = 129) to assess the impact of self-reported daily water intake on the estimated glomerular filtration rate (eGFR). The range distribution of water intake was as follows: − 1000 ml (n = 4), 1000–1500 ml (n = 23), 1500–2000 ml (n = 64), 2000–2500 ml (n = 57), 2500–3000 ml (n = 16), and 3000 − ml (n = 3). Donor age was significantly higher in the chronic-change group. In the control group, the ΔeGFR/year increase was correlated with water intake. However, the increase in the water intake of the chronic-change group significantly decreased ΔeGFR/year (1000–1500 ml: + 1.95 ml/min/1.73 m 2 and > 2000 ml: − 1.92 ml/min/1.73 m 2 , p = 0.014). This study suggested a potential influence of increased water intake on recipients with marginal grafts in living donor kidney transplantation.