Calculators › Donor Risk Index

Donor Risk Index (DRI)

Prediction of Deceased Donor Liver Graft Failure
Quantifies the relative risk of graft failure from a deceased donor liver based on donor characteristics. A DRI of 1.0 represents the reference risk; higher values indicate extended criteria donors with increased graft failure risk.
Liver Transplantation Donor Assessment ECD Hepatology
DRI Calculator
Donation Type
Graft Type

DRI Formula

DRI = exp[0.154 × (age 40–49)
+ 0.274 × (age 50–59)
+ 0.424 × (age 60–69)
+ 0.501 × (age ≥70)
+ 0.079 × (DCD)
+ 0.463 × (split/partial graft)
+ 0.422 × (cause: stroke)
+ 0.105 × (cause: anoxia)
+ 0.244 × (regional share)
+ 0.264 × (national share)
+ 0.010 × (CIT in hours)]

Reference donor = age <40, DBD, whole graft, trauma cause of death, local share, CIT = 0 h → DRI = 1.0. Each term is a binary (0 or 1) indicator except CIT which is continuous. Variables are additive in log space.

Interpretation

DRIRiskClinical Significance
<1.5LowStandard criteria donor — suitable for all recipients
1.5–1.9MarginalExtended criteria donor — consider recipient SOFT score before accepting
≥2.0HighECD — high risk of primary graft dysfunction; decline if recipient is high-risk (SOFT ≥31)

Clinical Application

  • DRI was derived from analysis of 20,023 liver transplants in the UNOS database (1995–2003) — one of the largest derivation cohorts for any transplant risk score
  • Each DRI unit increase corresponds to approximately 17% higher risk of graft failure at 3 years
  • DRI >2.0 combined with recipient SOFT >30 is associated with >50% graft failure at 1 year — this combination should be avoided whenever possible
  • Machine perfusion (hypothermic or normothermic) may partially mitigate donor risk in ECD organs — DRI alone should not replace clinical judgment when perfusion data are available
  • ET-DRI (Eurotransplant DRI, Braat et al. 2012) uses a similar but slightly modified formula with continuous donor age (natural log) rather than categorical tiers, validated specifically in European cohorts
  • Warm ischaemia time (relevant in DCD donors) and macrosteatosis grade are not included in the DRI — these must be assessed separately
  • The DRI does not distinguish between types of graft failure (primary non-function, early allograft dysfunction, ischaemic cholangiopathy) which have different mechanistic causes

References

  1. Feng S, et al. Characteristics associated with liver graft failure: the concept of a donor risk index. Am J Transplant. 2006;6(4):783–790.

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ET-DRI BAR Score SOFT Score EAD Criteria