Background: The classification of the deceased donors into standard and expanded criteria is associated with several limitations, mainly because standard criteria donors (SCD) can present other characteristics associated with poor outcomes, which the binary classification has not contemplated. The Kidney Donor Risk Index and the derived Kidney Donor Profile Index (KDPI) included additional variables and are better associated with long-term outcomes. However, the KDPI has not been validated for Brazilian donors. Thus, this study aimed to evaluate the performance of the KDPI in predicting outcomes for kidney transplant recipients (KTR) of SCD in the Brazilian population for whom the index was not previously validated, as part of the efforts to validate the index for Brazilian donors.

Methods: A retrospective single-center cohort enrolled 1,943 KTR who received a kidney of SCD between 2013 and 2017 and followed up to 2018. The primary outcome was composed of death, graft loss, and 1-year graft function < 30 mL/min/1.73m2, estimated by CKD-Epi (eGFR). Spearman’s rank correlation coefficient estimated the linear association between KDPI and eGFR. Multivariable analysis for the primary outcome was performed by logistic regression, and the C-statistic evaluated the discrimination of the risk prediction model.

Results: Recipients were 48.5 years old, 59.6% female, and 44.8% white. Donors were 41.0 years old, 61.6% male, and 52.2% white. Among donors, the prevalence of hypertension and diabetes was 24.9% and 3.8%, respectively. The main causes of brain death were subarachnoid hemorrhage (47.3%) and traumatic brain injury (41.2%). The median of KDPI was 52% (32; 69), stratified as follows: 28.9% of KDPI1-35, 18.6% of KDPI36-50, 48.3% of KDPI51-85, and 4.3% of KDPI>85. The incidence of delayed graft function and acute rejection (AR) was 58.6% and 18%, respectively. One-year eGFR was 52.8 mL/min. An inverse correlation was observed between 1-year eGFR and KDPI: R= -0.36; CI95%= -0.40; -0.32; P<0.001. The frequency of primary outcome was 14.4%: 4.4% of graft loss, 2.9% of death, and 7.7% of 1-year eGFR<30. The primary outcome was associated with a longer time in dialysis before transplantation (OR for each month = 1.003; P=0.03), CMV-related events (OR=1.32; P=0.04), AR (OR=2.13; P<0.001), and the KDPI strata. Compared with KDPI1-35, the OR was 1.62 (P=0.03), 2.27 (P<0.001) and 2.21 (P=0.01) for strata 36-50, 51-85 and >85, respectively. This modeling reached a C-statistic of 0.64 (0.61-0.68), P<0.001.

Conclusion: Despite not being previously validated for Brazilian donors, the KDPI significantly correlated with 1-year graft function in kidney transplant recipients of standard criteria donors. Furthermore, although the predictive model had reached a moderate discriminative power, the KDPI was an independent predictor of primary outcome composed of death, graft loss, and eGFR < 30 within 1-year after transplantation.