Public Release: 28-Jan-2008

Bethesda, MD (Jan. 28, 2008) – Patients with chronic hepatitis C (HCV) infection should not use marijuana (cannabis) daily, according to a study published in Clinical Gastroenterology and Hepatology, the official journal of the American Gastroenterological Association (AGA) Institute. Researchers found that HCV patients who used cannabis daily were at significantly higher risk of moderate to severe liver fibrosis, or tissue scarring. Additionally, patients with moderate to heavy alcohol use combined with regular cannabis use experienced an even greater risk of liver fibrosis. The recommendation to avoid cannabis is especially important in patients who are coinfected with HCV/HIV since the progression of fibrosis is already greater in these patients.

Researchers found a significant association between daily versus non-daily cannabis use and moderate to severe fibrosis when reviewing this factor alone. Other factors contributing to increased fibrosis included age at enrollment, lifetime duration of alcohol use, lifetime duration of moderate to heavy alcohol use and necroinflammatory score (stage of fibrosis). In reviewing combined factors, there was a strong (nearly 7-fold higher risk) and independent relationship between daily cannabis use and moderate to severe fibrosis. Gender, race, body mass index, HCV viral load and genotype, HIV coinfection, source of HCV infection, and biopsy length were not significantly associated with moderate to severe fibrosis.

Of the 328 patients screened for the study, 204 patients were included in the analysis. The baseline characteristics of those included in the study were similar to those excluded with the exception of daily cannabis use (13.7 percent of those studied used cannabis daily versus 6.45 percent of those not included). Patients who used cannabis daily had a significantly lower body mass index than non-daily users (25.2 versus 26.4), were more likely to be using medically prescribed cannabis (57.1 percent versus 8.79 percent), and more likely to have HIV coinfection (39.3 percent versus 18.2 percent).