Table 5 Comparison of risk scores for each solid organ
Organ | Risk score | Scoring method | Priority | Ethical and statistical concerns |
|---|---|---|---|---|
Liver | MELD 3.0 | 6–40, higher score means more medically urgent | Medical urgency | • The 1.33 additional points for the female sex lacks biological justification and contradicts the purpose of developing MELD as a purely objective score • Lack of flexibility. The discriminatory and predictive powers decreased with time • Not the unique best risk score for post-transplant mortality. Models with similar performance (e.g. OPOM) also exist |
Kidney | KDRI/KDPI/ETPS | 0-100%, assess graft failure risk compared to the reference recipient | Minimize re-transplantation | • Inclusion of race as a predictive variable • Removing race or replacing it with APOL1 had no significant effect on the model’s predictability • Longevity matching with KDPI and EPTS does not fully consider post-transplant quality of life |
Lung | Lung Allocation Score | 0-100, higher score means more medically urgent | Balance of post-transplant survival and medical urgency | • Conflict of values between WLAUC and PTAUC • Geographical limit results in local patients with lower LAS receiving transplantation earlier than slightly further patients with higher LAS • Clinically significant error in prediction with increased inaccuracy with higher LAS scores |
Heart | Heart Tier System (2018) | Tier 1–6, each with its own qualifying criteria. No stratification within tiers | Medical urgency | • Increases in short-term MCS device usage with changes in scoring criteria • Center-dependent ranking and multi-listing are possible • Insufficient stratification tiers and lack of stratification within tiers • Continuous variables are treated as categorical ones • Very limited discriminatory power |