Integrated prediction of delayed graft function after kidney transplantation using the renal artery resistive index and pretransplant hematological parameters

Delayed graft function (DGF) remains a frequent early complication after kidney transplantation and is associated with prolonged hospitalization and inferior graft outcomes. This retrospective cohort study evaluated whether the renal artery resistive index (RI) combined with pretransplant hematological parameters could improve DGF prediction. Adult recipients who underwent kidney transplantation between January 2022 and December 2024 at Shulan (Hangzhou) Hospital were screened; 280 patients were included and categorized into a DGF group (n = 88) or a non-DGF group (n = 192) according to the requirement for dialysis within the first posttransplant week. Pretransplant blood tests and postoperative Doppler-derived RI were collected. Univariate analyses demonstrated significant between-group differences in RI, serum creatinine, blood urea nitrogen, and albumin, whereas demographic factors, primary kidney disease, dialysis characteristics, leukocyte indices, and immunosuppressive regimen did not differ significantly. In multivariable logistic regression, RI, serum creatinine, blood urea nitrogen, and albumin independently predicted DGF. Receiver operating characteristic analysis showed strong discriminatory performance for the combined model (area under the curve = 0.923; 95% confidence interval: 0.888-0.957), yielding high sensitivity (90.91%) and moderate specificity (79.69%). Stratification by the optimal combined-indicator cutoff further demonstrated associations with postoperative organ dysfunction severity and patient-reported quality of life. These findings support incorporating RI with routine hematological parameters to facilitate early risk stratification for DGF after kidney transplantation.