Associations between deceased-donor urine injury biomarkers and kidney transplant outcomes

Abstract

Assessment of deceased-donor organ quality is integral to transplant allocation practices, but tools to more precisely measure donor kidney injury and better predict outcomes are needed. In this study, we assessed associations between injury biomarkers in deceased-donor urine and the following outcomes: donor AKI (stage 2 or greater), recipient delayed graft function (defined as dialysis in first week post-transplant), and recipient 6-month eGFR. We measured urinary concentrations of microalbumin, neutrophil gelatinase- associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), IL-18, and liver-type fatty acid binding protein (L-FABP) from1304 deceased donors at organ procurement, among whom112 (9%) had AKI. Each biomarker strongly associated withAKI in adjusted analyses.Among2441 kidney transplant recipients, 31%experienced delayed graft function, and mean6SD6-month eGFRwas 55.7623.5 ml/min per 1.73m2. In analyses adjusted for donor and recipient characteristics, higher donor urinary NGAL concentrations associated with recipient delayed graft function (highest versus lowestNGAL tertile relative risk, 1.21; 95%confidence interval, 1.02 to 1.43). Linear regression analyses of 6-month recipient renal function demonstrated that higher urinary NGAL and L-FABP concentrations associated with slightly lower 6-month eGFR only among recipients without delayed graft function. In summary, donor urine injury biomarkers strongly associate with donor AKI but provide limited value in predicting delayed graft function or early allograft function after transplant.