The effect of cholecalciferol supplementation on allograft function in incident kidney transplant recipients: A randomized controlled study

It is unknown whether cholecalciferol supplementation improves allograft outcomes in kidney transplant recipients (KTRs). We conducted a single‐center randomized, double‐blind, placebo‐controlled trial of daily 4000 IU cholecalciferol supplementation in KTRs at 1‐month posttransplant. The primary endpoint was the change in eGFR from baseline to 12‐month posttransplant. Secondary endpoints included severity of interstitial fibrosis and tubular atrophy (IFTA) at 12‐month posttransplant and changes in urinary biomarkers. Of 193 randomized patients, 180 participants completed the study. Changes in eGFR were 1.2 mL/min/1.73 m(2) (95% CI; −0.7 to 3.1) in the cholecalciferol group and 1.8 mL/min/1.73 m(2) (95% CI, −0.02 to 3.7) in the placebo group, with no significant between‐group difference (−0.7 mL/min/1.73 m(2) [95% CI; −3.3 to 2.0], p = 0.63). Subgroup analyses showed detrimental effects of cholecalciferol in patients with eGFR <45 mL/min/1.73 m(2) (P(interaction) <0.05, between‐group difference; −4.3 mL/min/1.73 m(2) [95% CI; −7.3 to −1.3]). The degree of IFTA, changes in urine albumin‐to‐creatinine ratio, or adverse events including hypercalcemia and infections requiring hospitalization did not differ between groups. In conclusion, cholecalciferol supplementation did not affect eGFR change compared to placebo among incident KTRs. These findings do not support cholecalciferol supplementation for improving allograft function in incident KTRs. Clinical trial registry: This study was registered in the University Hospital Medical Information Network Clinical Trials Registry (UMIN‐CTR) as UMIN000020597 (please refer to the links below). UMIN‐CTR: https://upload.umin.ac.jp/cgi‐open‐bin/ctr_e/ctr_view.cgi?recptno=R000023776