Influence of Cannabis Use on Severity of Hepatitis C Disease

Background & Aims: Complications of HCV infection are primarily related to the development of advanced fibrosis and whether cannabis use is a risk factor for more severe fibrosis is controversial. Methods: Baseline data from a prospective cohort study of 204 persons with chronic HCV infection were used for analysis. The outcome was fibrosis score on biopsy, and the primary predictor evaluated was daily cannabis use. Results: The median age of the cohort was 46.8 years, 69.1% were male, 49.0% were white, and the presumed route of infection was injection drug use in 70.1%. The median lifetime duration and average daily use of alcohol were 29.1 years and 1.94 drink equivalents per day, respectively. Cannabis use frequency (within prior 12 months) was daily in 13.7%, occasional in 45.1%, and never in 41.2%. Fibrosis stage, assessed by the Ishak method, was F0, F1–2, and F3–6 in 27.5%, 55.4%, and 17.2% of subjects, respectively. Daily compared with non-daily cannabis use was significantly associated with moderate to severe fibrosis (F3–6 vs F1–2) in univariate (odds ratio [OR], 3.21; 95% confidence interval [CI], 1.20–8.56, P = .020) and multivariate analyses (OR, 6.78; 95% CI, 1.89–24.31, P = .003). Other independent predictors of F3–6 were ≥11 portal tracts (compared with <5, OR, 6.92; 95% CI, 1.34–35.7, P = .021) and lifetime duration of moderate to heavy alcohol use (OR per decade, 1.72; 95% CI, 1.02–2.90, P = .044). Conclusions: Daily cannabis use is strongly associated with moderate to severe fibrosis, and HCV-infected individuals should be counseled to reduce or abstain from cannabis use.

Abbreviations used in this paper: CI, confidence interval, HCV, hepatitis C virus, HIV, human immunodeficiency virus, IDU, injection drug use, IQR, interquartile range, Q1 and Q3, OR, odds ratio