Marijuana use in potential liver transplant candidates

Concern exists that liver transplant center substance abuse policies may have an inappropriate and disproportionate impact on marijuana users. Our hypothesis is that patients with chronic liver disease who were marijuana users will have inferior survival. This is a retrospective (1999-2007) cohort study. The primary outcome measure is time-dependent, adjusted patient survival from the time of liver transplant evaluation. The primary exposure variable is a positive cannabinoid toxicology screen during the liver transplant evaluation period. Overall, 155 patients qualified as marijuana users while 1334 patients were marijuana non-users. Marijuana users were significantly (p < 0.05) younger (48.3 vs. 52.1), more likely to be male (78.1% vs. 63.0%), have hepatitis C (63.9% vs. 40.6%) and were less likely to receive a transplant (21.8% vs. 14.8%). Marijuana users were more likely to use tobacco, narcotics, benzodiazepines, amphetamines, cocaine or barbiturates (p < 0.05). Unadjusted survival rates were similar between cohorts. Upon multivariate analysis, MELD score, hepatitis C and transplantation were significantly associated with survival, while marijuana use was not (HR 1.09, 95% CI 0.78-1.54). We conclude that patients who did and did not use marijuana had similar survival rates. Current substance abuse policies do not seen to systematically expose marijuana users to additional risk of mortality.