Review of liver transplantation candidacy and outcomes among patients who use cannabis: Is it time for a change in policy?

Abstract

Recreational cannabis was legalized in Canada in 2018. A controversial contraindication for liver transplantation is cannabis. There is currently no consensus regarding cannabis use in liver transplant candidates. We aim to investigate liver transplantation candidacy and outcomes among cannabis users. English peer-reviewed studies on PubMed and Google Scholar were searched on September 9, 2022, using keywords including "cannabis," "liver transplantation," and their synonyms. Titles and abstracts were screened, followed by full texts. Reference lists were reviewed. Studies that investigated liver transplantation candidacy and outcomes among cannabis users were included. The proportion of patients listed for liver transplantation was significantly less among cannabis users than among non-users. Time to listing was longer for cannabis users than non-users. The incidence of delisting was similar. There is an inconsistency between transplant centres regarding transplantation candidacy for cannabis users. While only 14% of Canadian centres had a policy in place and preferred candidates to abstain or decrease cannabis use before transplantation, a third of Canadian centres rejected cannabis users. Observational studies failed to demonstrate significant differences in patient survival between pre-transplantation cannabis users and non-users. However, self-reported mental health ratings were worse in post-transplantation cannabis users than in non-users and former users. Current observational data do not support a link between cannabis use and poor patient survival post-transplantation. However, high-quality prospective studies are needed to better elucidate the impact of cannabis use on liver transplantation outcomes. Liver transplant candidacy should be evaluated through a multidisciplinary and comprehensive approach considering all relevant psychosocial factors.