The impact of donor and recipient weight incompatibility on renal transplant outcomes.

BACKGROUND: Donor/recipient size mismatching and correlation to allograft outcome remains poorly defined. This study assessed the impact of donor body weight (DBW) to recipient body weight (RBW) ratio on allograft function and survival. METHODS: A total of 898 deceased donor renal transplant recipients were included in the study. Patients were divided into quartiles depending on the ratio of DBW/RBW: Q1 (≤ 0.88), Q2 (0.89-1.00), Q3 (1.01-1.22) and Q4 (> 1.22). Donor and recipient characteristics were obtained from the national kidney transplant service database. Serum creatinine and estimated glomerular filtration rate (eGFR) at 1 and 5 years after transplant were compared. RESULTS: Q4 patients had a higher eGFR 1 year post-transplant (median 59.5 ml/min, IQR 46.8-76.2) compared to Q1-Q3 which had median eGFRs of 54.3, 54.8 and 55.3 ml/min, respectively (p < 0.001). At 5 years post-transplant, there were modest differences in the eGFR across the four quartiles, Q1-4 with median eGFRs of 56.9, 61.1, 61.2 and 58.6 ml/min, respectively (p = 0.02). However, there were no significant differences in 1- and 5-year allograft survival between groups. CONCLUSIONS: In the setting of deceased donor renal transplantation, mismatching of donor to recipient weight had no impact on 5-year allograft survival, but a low DBW/RBW ratio is modestly associated with lower eGFR.