Effect of Recipient Variables on Transplant Survival Following Marginal Kidney Donation: Analysis of a Mate Kidney Cohort.

BACKGROUND Transplantation using kidneys from older donors or those with specific risk factors (marginal kidneys) offers improved outcomes compared to remaining on dialysis. Matched-pair analysis potentiates control for confounding donor factors and the impact of recipient characteristics on transplant survival. MATERIAL AND METHODS Data from 200 transplants using marginal deceased donors were retrospectively analyzed. Paired comparisons between mate kidney recipients, McNemar's test, and multivariable Cox regression were performed to identify recipient factors and histological features from zero-time biopsy associated with graft survival. RESULTS Graft survival was significantly longer in recipients with shorter pre-transplant dialysis exposure (mean 58.10 vs 68.86 months, P=0.001) and fewer HLA mismatches (3.40 vs 3.78, P=0.013). Severe acute tubular injury (ATI) in pre-implantation biopsy was associated with reduced graft survival (P=0.04). In multivariable Cox regression, the presence of severe ATI (P<0.001), older recipient age (HR=0.1 per year, P=0.002), HLA mismatches (HR=1.21, P=0.011), and elevated 1-year serum creatinine level (HR=0.72, P=0.030) remained independently associated with shorter graft survival. CONCLUSIONS Matched-pair analysis and multivariable modelling identified recipient dialysis duration, age, HLA mismatches,1-year serum creatinine, and pre-transplant biopsy findings, particularly severe ATI, as key predictors of graft survival in marginal kidney transplantation. These insights may support improved recipient selection and post-transplant management of marginal-donor kidneys.