Reassessing the survival benefit of deceased donor liver transplantation: retrospective cohort study

Abstract

Introduction: Currently in the United States, deceased donor liver transplant (DDLT) allocation priority is based on the model for end-stage liver disease including sodium (MELD-Na) score. The United Network for organ sharing's 'Share-15' policy states that candidates with MELD-Na scores of 15 or greater have priority to receive local organ offers compared to candidates with lower MELD-Na scores. Since the inception of this policy, major changes in the primary etiologies of end-stage liver disease have occurred and previous assumptions need to be recalibrated.

Methods: The authors retrospectively analyzed the Scientific Registry of Transplant Recipients database between 2012 and 2021 to determine life years saved by DDLT at each interval of MELD-Na score and the time-to-equal risk and time-to-equal survival versus remaining on the waitlist. The authors stratified our analysis by MELD exception points, primary disease etiology, and MELD score.

Results: On aggregate, compared to remaining on the waitlist, a significant 1-year survival advantage of DDLT at MELD-Na scores as low as 12 was found. The median life years saved at this score after a liver transplant was estimated to be greater than 9 years. While the total life years saved were comparable across all MELD-Na scores, the time-to-equal risk and time-to-equal survival decreased exponentially as MELD-Na scores increased.

Conclusion: Herein, the authors challenge the perception as to the timing of DDLT and when that benefit occurs. The national liver allocation policy is transitioning to a continuous distribution framework and these data will be instrumental to defining the attributes of the continuos allocation score.

Figure 1

One-year Mortality Risk Across MELD-Na Categories for All Patients Receiving Deceased Donor Liver Transplantation (DDLT) versus Remaining on the Waitlist, 2011–2021. Relative hazard ratios (HR) were calculated for all patients at 1-year on the waitlist and post-transplantation across ten MELD categories: 6–10, 11–13, 14–16, 17–19, 20–23, 24–26, 27–30, 31–34, 35–38, and 39>. (A) 1-year, unadjusted hazard ratios and (B) covariate-adjusted Cox proportional hazard ratios were reported with 95% CI and significance thresholds. Unadjusted hazard ratios were calculated by dividing the mortality rate of transplanted patients by the mortality rate of waitlisted candidates. Adjusted hazard ratios were calculated using Cox proportional hazard regression and were adjusted for age at listing, sex, and primary diagnosis. Significance thresholds were labeled as: *P<0.05, **P<0.01, and ***P<0.001.

Figure 2

Life Years Saved Following Deceased Donor Liver Transplantation for All DDLT Recipients. Life years from transplant or LYFT was calculated for all MELD-Na groups using parametric survival regression and extrapolated to 10 000 days or 27.38 years. The overall projected survival benefit or life years saved was calculated by subtracting the median days on the waitlist from LYFT. Median life years saved ranged from 8.2 to 13.4. All LYFT projections were highly significant with P values less than 0.001.