Impact of the MELD-based allocation system on waitlist mortality and transplant rates in Japan: A single-center study

Background: Although the number of deceased donors in Japan has been increased and exceeded 100 cases in 2023, liver transplantation still largely depends on living donors. To improve equity and fairness, the allocation policy was revised to a MELD score-based system in May 2019. However, waitlist mortality and deceased donor liver transplantation rates under this system have not been fully evaluated.
Aims: To evaluate waitlist mortality and transplant rates for deceased donor liver transplantation in Japan.
Methods: We retrospectively evaluated waitlist mortality and transplant rates per 100 patient-years over a 10-years period from January 1, 2016, to December 31, 2025, at Hokkaido University Hospital.
Results: A total of 111 patients were registered during the study period. Of these, 48 died while on the waitlist and 31 underwent deceased donor liver transplantation. Twenty-two patients were removed from the waitlist, including 2 who received living donor liver transplantation, and 10 remained on the waitlist at the end of the study. The annual transplant rate in the first 5 years from January 1, 2016 (mean, 11.2 per 100 patient-years) was comparable to that in the most recent 5 years (12.5 per 100 patient-years). In contrast, the waitlist mortality rate increased markedly in the recent 5-year period (32.3 per 100 patient-years) compared with the earlier 5-year period (18.3 per 100 patient-years). Notably, waitlist mortality among patients with primary biliary cholangitis (PBC) increased from 41.4 to 197.7 per 100 patient-years, whereas the transplant rate for PBC declined from 61.9 per 100 patient-years in the earlier period to 0 per 100 patient-years in the most recent period.
Conclusion: Despite an increase in the number of deceased donors, the MELD-based allocation system may be associated with increased waitlist mortality in recent years, particularly among patients with PBC. These findings highlight the need for revision of the allocation system based on nationwide evaluation in Japan.