Case-crossover study of hospitalization for acute hepatitis in Chinese herb users

Background and Aim: Despite the increase in popularity of herbal products, there is growing concern over potential health hazards caused by the Chinese herbal medicines (CHMs) that are regularly reimbursed under the National Health Insurance system in Taiwan. This study attempts to determine the association between CHM prescriptions and acute hepatitis-related hospitalizations. Methods: A case-crossover study was designed on 200 000 randomly selected individuals from the National Health Insurance Research Database who were then followed from 1997 to 2002. All medications taken in the 30- and 60-day periods prior to hospitalization were explored and compared with four control periods (the 180- and 360-day periods prior to and after the hospitalization). A conditional logistic regression model was then constructed to determine the odds of CHM being prescribed during these risk periods. Results: There were a total of 12 cases with nonviral, nonalcoholic hepatitis patients who took CHM prescriptions during the 30-day risk or control periods. After adjustment for conventional hepatotoxic drugs, the odds ratio during the 30-day risk period was 3.4 (95% confidence interval [CI]: 1.1, 9.8) for nonviral, nonalcoholic acute hepatitis. A detailed historical review of CHMs for each patient revealed that the odds ratio increased to 4.2 for those prescribed formulae containing Radix Paeoniae (95% CI: 1.1, 15.7) and Radix Glycyrrhizae (95% CI: 1.2, 15.2). Conclusions: Chinese herbal users revealed a slightly increased risk of acute hepatitis. We therefore recommend pharmacovigilance and active surveillance for CHMs suspected with hepatotoxicity.