Transplant Donor Risk Index

The Kidney Donor Risk Index (KDRI) Calculator estimates the relative risk of graft failure from a deceased donor kidney based on donor characteristics. The KDRI is then mapped to the Kidney Donor Profile Index (KDPI), a percentile ranking that places the donor organ on a scale from 0% (lowest risk) to 100% (highest risk) relative to all deceased donor kidneys recovered in the previous year. The KDPI is used in the United States organ allocation system to match donor kidneys with appropriate recipients.

The KDRI was developed by Rao and colleagues using data from over 69,000 deceased donor kidney transplants performed between 1995 and 2005 in the United States, with outcomes tracked through the Scientific Registry of Transplant Recipients (SRTR). The model identifies donor factors independently associated with graft failure and combines them into a single risk score. Key donor variables include age, height, weight, terminal creatinine, history of hypertension, history of diabetes, cause of death (cerebrovascular accident vs. other), and donation type (DCD vs. DBD).

The KDPI was introduced in 2014 as a simplified clinical tool derived from the KDRI. It converts the raw KDRI score to a percentile based on the distribution of KDRI scores among all recovered deceased donor kidneys in a reference year. A KDPI of 20% means the kidney has a KDRI better than 80% of all recovered kidneys. Lower KDPI values indicate lower expected risk of graft failure. KDPI has replaced the previous Extended Criteria Donor (ECD) classification, which was a binary system that categorized donors as standard or extended criteria without the granularity of a continuous risk score.

The clinical significance of KDPI lies in organ allocation and informed consent. Under the current US allocation policy, kidneys with KDPI 0-20% are offered to the longest-waiting candidates first (regardless of geographic proximity), while kidneys with KDPI 21-85% follow standard allocation algorithms, and kidneys with KDPI 85-100% are offered more broadly to avoid discard. Recipients who agree to accept higher KDPI kidneys may receive transplants sooner, as there is less competition for these organs. For many patients, receiving a higher KDPI kidney still provides significantly better outcomes than remaining on dialysis.

The simplified model presented in this calculator captures the major donor risk factors but does not include all 10 variables in the full KDRI model (which additionally includes race, hepatitis C status, and cold ischemia time). The full KDRI calculation is performed by UNOS using complete donor data at the time of organ offer. This calculator provides an estimate useful for educational purposes and preliminary donor assessment.

Important considerations when interpreting KDPI include the fact that it reflects donor organ quality only and does not account for recipient factors (age, sensitization, comorbidities) that also influence transplant outcomes. A kidney with KDPI 85% transplanted into a 70-year-old recipient may provide excellent outcomes because the kidney only needs to last 10-15 years, while the same kidney in a 30-year-old recipient carries a higher risk of graft failure within the recipient's lifetime.