# Equitable Donor Assessment Model of Deceased Donor Kidney Quality

## TL;DR

This paper introduces EDAM, a new model for assessing kidney donor quality that aims to improve fairness in organ allocation by focusing on donor-specific factors.

## Contribution

The novel EDAM model isolates intrinsic donor graft-failure risk, independent of recipient factors, to provide a more equitable kidney donor assessment.

## Key findings

- EDAM demonstrated strong discrimination (C-index = 0.69) and good calibration across US regions.
- Nearly half of kidneys labeled high-risk by KDPI were reclassified as low-risk by EDAM, achieving similar 10-year graft survival.
- EDAM's donor-centric approach could refine organ allocation policies and enhance fairness in kidney transplantation.

## Abstract

The Kidney Donor Profile Index (KDPI) guides organ allocation but blends donor and recipient influences, potentially misclassifying organ quality and contributing to inequity. We developed the Equitable Donor Assessment Model (EDAM), a donor-focused index that isolates intrinsic graft-failure risk independent of recipient survival.

Using the United Network for Organ Sharing (UNOS) data (2010–2020; N = 122,646), we modeled death-censored graft failure with death as a competing event using Fine-Gray regression. Donor coefficients were adjusted for recipient and transplant covariates—including human leukocyte antigen (HLA) mismatch and ischemia time—to derive donor-specific subhazard ratios (SHRs) for the EDAM score. Performance was evaluated using Harrell’s C-index and internal-external cross-validation across 5 geography-aligned US super-regions.

Higher donor age, diabetes, hypertension, stroke as cause of death, proteinuria, cytomegalovirus (CMV) seropositivity, and elevated creatinine independently increased graft-failure risk. EDAM demonstrated robust discrimination (C-index = 0.69) and excellent calibration across US regions (pooled slope = 1.02; intercept = −0.002). Stratification into 5 data-driven categories showed a graded rise in cumulative incidence of graft failure (Gray’s P < 0.05). Nearly half of kidneys classified as moderate-to-high KDPI (≥ 0.20) were reclassified as low-risk by EDAM (< 0.80) and achieved identical 10-year graft survival to conventional KDPI < 0.20 organs.

EDAM provides an equitable, donor-centric framework for assessing kidney quality. Although these categorical thresholds were derived in a data-driven manner within the US system and require external validation in international cohorts, EDAM’s ability to safely expand the low-risk pool without compromising outcomes suggests it could significantly refine allocation policy and enhance fairness in kidney transplantation.