Variation in intention-to-treat survival by MELD subtypes: all models created for end-stage liver disease are not equal.

ABSTRACT

BACKGROUND & AIMS: Kidney dysfunction is a major determinant of prognosis in patients with decompensated cirrhosis awaiting transplantation. We hypothesized that for identical MELD scores at listing, outcomes before and after liver transplantation may vary if the predominant driver of the MELD score is serum creatinine versus serum bilirubin or INR. METHODS: We evaluated all adult patients registered for liver transplantation (LT) between 2016 - 2020 and excluded patients receiving MELD exceptions or undergoing dual organ transplantation. Using K-Means clustering analysis, we classified each patient as MELD-Br, MELD-INR or MELD-Cr depending on the dominant variable for their MELD score. The primary outcome was intent-to-treat survival, defined as survival within 1 year from listing with or without LT. RESULTS: MELD scores of LT waitlist registrants clustered into 3 subtypes MELD-Br (n=13,658), MELD-INR (n=13,809), and MELD-Cr (n=12,412). One-year ITT survival was 78% (MELD-Br), 75% (MELD-INR), and 65% (MELD-Cr), p<0.01. ITT survival was lower for each MELD subtype for females compared to males (e.g. MELD Cr 63% females vs 67% males, p<0.0001). MELD-Cr subtype had the highest MELD at listing (MELD Cr 23.4 vs MELD-Br 19.2 vs MELD INR 21.0) and the largest decline in MELD over 3 months (23% vs. 12% vs 21%). In adjusted analyses including MELD Na, MELD-Cr compared to the other subtypes was associated with higher WL mortality (HR 1.339, 95% CI 1.279-1.402) and lower LT rates (HR 0.688, 95% CI 0.664-0.713). CONCLUSIONS: For equivalent listing practices, registrants with MELD-Cr subtype have lower ITT survival. MELD subtype may serve as a more sophisticated variable for dynamic assessment of risk of mortality, to inform models for organ allocation. IMPACT AND IMPLICATIONS The MELD score is an excellent predictor of waitlist mortality; however, our work highlights that the driver of a patient's score MELD score matters and particularly those driven by elevated creatinine have a lower 1-year ITT mortality. The 1-year ITT mortality is also lower for women compared to men within the Cr-dominant subtype. These results are important for physicians and patients undergoing LT evaluation as creatinine may serve as a marker of prognosis and even if the creatinine improves the prognosis remains poor, necessitating discussion about alternative pathways for transplant. Our work also highlights that the type of kidney injury matters, in that those AKI were more likely to die or remain on the waitlist compared to those with CKD within the creatinine dominant subtype.