Impact of COVID-19 on liver transplantation in hong kong and singapore: A modelling study with forecasts till 2025

ABSTRACT

Background: Liver transplantation (LT) activities during the COVID-19 pandemic have been curtailed in many countries which has led to increased percentage of waitlist deaths. The impact of various policies restricting LT on outcomes of patients on the LT waitlist is unclear. This study aims to model effects of various scenarios and duration of LT disruption on outcomes. Methods: Using nationwide data from Hong Kong and Singapore of 571 patients between January 2016 and May 2020, we utilized a continuous time Markov chains model approach to evaluate the three following outcomes: (a) overall survival, (b) proportion of waitlist dropout in HCC patients, and (c) proportion of patients that developed acuteon-chronic liver failure (ACLF) while on the LT waitlist under the five scenarios. The five scenarios were (1) no limitation to LT (both deceased donor liver transplant [DDLT] and living donor liver transplant [LDLT]), (2) no limitation to DDLT, only urgent (acute liver failure [ALF] or ACLF) LDLT allowed, (3) only urgent LT (DDLT and LDLT) allowed, (4) only DDLT, no LDLT allowed and (5) complete cessation of LT. For each scenario, varying periods of 1-, 3-, 6- and 12-month duration of disruption were simulated. Results: With complete cessation of LT, the projected 1-year overall survival (OS) decreased by 3.6%, 10.51% and 19.21% for a 1-, 3- and 6-month disruption respectively when compared to no limitation to LT, while 5-year OS decreased by 5.3%, 15.81%, and 31.11% respectively. When only urgent LT was allowed, the projected 1-year OS decreased by a similar proportion 3.1%, 8.41% and 15.20% respectively. When only DDLT was allowed to take place, the 1-year projected OS decreased by a smaller proportion - 1.9%, 6.30% and 10.79% for a 1-, 3-, 6-month disruption respectively. When DDLT and only urgent LDLT were allowed, 1-year projected OS was similar to when only DDLT was allowed, at 1.2%, 5.1% and 8.85% for a 1-, 3- and 6-month disruption respectively (Figure 1A). Complete cessation of LT activities resulted in an increased projected incidence of ACLF at 1-year by 17.6%, 49.1% and 95.5%, as well as an increase in hepatocellular carcinoma (HCC) dropout resulting in delisting at 1-year by 31.8%, 107.96% and 176.06% for a 1-, 3- and 6- month disruption respectively (Figure 1B). When only urgent LT was allowed, HCC dropout and ACLF incidence were comparable to the rates seen in the scenario of complete LT cessation. Conclusion: A short and wide-ranging disruption to LT results in better outcomes compared with a longer duration of partial restrictions. Findings from our study provide useful guidance for LT units worldwide in navigating the peaks and troughs of COVID-19 surges and highlight the impact of LT disruption on waitlisted patients during this prolonged pandemic. Once the peak of the COVID-19 wave has passed, DDLT at minimum should be resumed as soon as possible.