Kidney transplant recipients continue to face a significant long-term risk of allograft failure. We aimed to evaluate early renal function recovery following living-donor nephrectomy and to investigate their relationship with long-term allograft function.

We included 2575 consecutive living-donor kidney transplantations between January 1, 2007, and December 31, 2022. We collected information on pre- and post-donation kidney function, and examined the risk of 5-year and 10-year allograft failure.

The median relative changes were 21.1% (IQR: 7.1% to 36.8%) for creatinine and -13.2% (IQR: -26.1% to -3.4%) for eGFR after living donor nephrectomy. Receiver Operation curves reported stronger associations between allograft function and post-donation kidney function as well as the relative change, but not pre-donation kidney function. A 10% relative increase in creatinine was associated with a 37% higher risk of allograft failure (HR:1.367, 95%CI: 1.262-1.479, P<0.001). Non-linear analyses revealed a J-shaped relationship between allograft failure and both post-nephrectomy kidney function and the relative changes. Further stratified analyses supported this finding in recipients whose donors had an eGFR < or > 90 ml/min/1.73 m2 at donation. Last, incorporating the creatinine relative change into transplant evaluations improved the prediction of 5-year and 10-year allograft failure beyond the iBOX risk score, as demonstrated by multivariable Cox analyses and two machine learning models (Xgboost, Random Forest).

Early renal function recovery after donor nephrectomy was independently associated with long-term allograft function. Early monitoring of post-donation kidney function recovery may enhance the detection of long-term risk of allograft failure.