Clinical indicators of slow graft function and outcome after pediatric kidney transplantation

Background Lesser degrees of perioperative ischemia–reperfusion injury that does not require dialysis may nonetheless influence allograft outcomes, necessitating evaluation of suitable surrogate indicators of perioperative allograft injury. Methods This retrospective analysis of pediatric kidney transplants evaluated two indicators representing pace and completeness of recovery, for association with 12‐month estimated glomerular filtration rate (eGFR) and first‐year rate of eGFR decline: time to creatinine nadir (TTN) and ratio of recipient/donor unadjusted GFR (uGFR R/D ) at 1‐month post‐transplant. Donor, recipient, and perioperative risk factors were tested further for association with these 2 indicators. Results 179 patients (190 transplants) aged 13 (IQR 7–17) years and 56% male were included. Twelve‐month eGFR was strongly associated with unadjusted GFR at 1 month (uGFR 1M , p < .001) and uGFR R/D ( p = .003), but not with TTN. None of the indicators was associated with the rate of subsequent eGFR decline after 1‐month post‐transplant. As a potential surrogate indicator, uGFR 1M is effectively modeled by TTN and uGFR R/D (adjusted R 2 = 0.57) and is associated with 12‐month eGFR ( β = 0.81 ± 0.08; p < .001). Clinical factors associated with uGFR R/D included donor uGFR ( p < .001), BSA ( p = .026), age ( p = .074), and recipient BSA ( p < .001). Factors associated with pace of recovery (TTN) included donor uGFR ( p = .018), type ( p = .019), and recipient BSA ( p = .022). Conclusions The uGFR R/D ratio, but not TTN, is a useful indicator of perioperative allograft damage that is associated with one‐year functional outcome; and uGFR 1M is a potential early surrogate outcome. Donor, recipient, and perioperative factors that are associated with slow allograft function are identified.