Association between donor albuminuria and the risk of graft failure in living-donor kidney transplantation: a retrospective cohort study.

BACKGROUND

Kidney donors with marginal characteristics, including those presenting with albuminuria, are increasingly being accepted to alleviate organ shortages in transplantation. However, high-quality evidence establishing the association between pre-donation donor albuminuria and graft survival remains limited.

METHODS

In this retrospective cohort study, we analyzed data from living-donor kidney transplants performed between 2017 and 2023. Donor-recipient pairs were stratified based on pre-donation urinary albumin-to-creatinine ratio (uACR) into High-uACR (uACR ≥30 mg/g) and Low-uACR (uACR <30 mg/g) groups, consistent with Kidney Disease: Improving Global Outcomes (KDIGO) criteria. The primary outcome was death-censored graft failure. Statistical analyses included Kaplan-Meier survival curves, multivariable Cox models, interaction and sensitivity analyses.

RESULTS

The study included 1674 living-donor kidney transplantation pairs, comprising 120 in the High-uACR group and 1554 in the Low-uACR group. Recipients in the High-uACR group exhibited a higher incidence of death-censored graft failure compared with those in the Low-uACR group (14.17% [17/120] vs. 2.19% [34/1554]; P < .001). After full adjustment, the High-uACR group was associated with a 2.13-fold increased risk of death-censored graft failure (adjusted hazard ratio [HR] = 2.13, 95% confidence interval [CI] = 1.02-4.46, P = .044). Interaction analysis revealed that the risk was amplified among recipients whose donors had both elevated uACR and hypertension/diabetes (HR = 4.73, 95% CI = 1.93-11.62, P = .001), compared to the reference group (Low-uACR donors without hypertension/diabetes). This association remained consistent across subgroup analyses stratified by donor pre-donation estimated glomerular filtration rate ([eGFR] ≥90 or <90 mL/min/1.73m2). Sensitivity analyses incorporating repeated uACR measurements, and competing risk analyses reported similar results.

CONCLUSION

Elevated uACR in living donors had moderate predictive power for graft failure after kidney transplantation. Further studies should be conducted to explore the clinical utility of uACR within a comprehensive risk assessment framework to improve recipient risk stratification and support informed decision-making in donor selection.