Assessment of organ quality is integral to allocation, yet existing tools have a limited ability to predict important transplant outcomes. We evaluated whether injury biomarkers, measured in deceased donor urine at procurement, are associated with 1) donor acute kidney injury (AKI) and 2) 6-month kidney allograft function.

Methods: In this deceased-donor cohort from 5 organizations, we measured concentrations of albumin, neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) from procurement urine samples. We defined donor AKI as ≥2-fold rise in serum creatinine (Scr) from admission to the terminal value (at least AKI stage 2). We estimated 6-month recipient glomerular filtration rate (eGFR) based on Scr reported by centers to UNOS. Biomarker values were log-transformed for normality. We fit multivariable models for the outcomes and adjusted for donor and recipient variables as appropriate. We also examined the association of biomarkers with 6-month eGFR, stratified by delayed graft function (DGF).

Results: 1301 donors yielded 2435 individual transplants. AKI occurred in 111 (9%) donors. Compared to donors without AKI, the levels of all 3 biomarkers were higher in donors with AKI [adjusted RR 2.1 (IQR 2.82, 2.44), 1.71 (1.57, 1.87) and 1.26 (1.09, 1.44) per unit increase in albumin, NGAL and KIM-1, respectively]. DGF occurred in 756 (31%) recipients and mean 6-month eGFR was 56±24 ml/min/1.73m². In linear regression models adjusted for donor characteristics, albumin and NGAL were independently associated with 6-month recipient eGFR. Adjusted for donor and recipient characteristics, linear regression models revealed a significant interaction between these biomarkers and DGF. In recipients without DGF, 6-month eGFR was 1.5 (0.21, 2.80) or 0.7 (0.02, 1.38) ml/min/1.73m² lower for each unit increase in donor urine albumin or NGAL, respectively. In recipients with DGF, however, there were no significant associations between these 2 biomarkers and 6-month eGFR. There were also no significant associations between donor KIM-1 and recipient 6-month eGFR.

Conclusions: Structural AKI in deceased donors, as measured by urine albumin and NGAL, is associated with modest reductions in 6-month function for allografts that do not experience DGF. Donor injury may be an important independent measure of organ quality that merits further investigation.

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