Background: Hepatotoxicity is one of the most serious adverse effects of anti-tuberculosis drugs (ATD). Although many risk factors have been associated with ATD-induced hepatotoxicity, their influence on hepatitis severity has not been studied systematically.
Objectives: To evaluate whether the presence of hepatotoxicity risk factors (advanced age, chronic liver disease, abuse of alcohol or other drugs or malnutrition) influences the severity of ATD-induced hepatotoxicity.
Design: A prospective cohort study of 471 active tuberculosis patients treated with isoniazid, rifampicin and pyrazinamide and followed in a tuberculosis clinic between January 1998 and July 2002. Incidence of hepatotoxicity and its severity according to the presence or absence of ATD-induced hepatitis risk factors was evaluated.
Results: The incidence of ATD-induced hepatotoxicity (serum transaminase > 3 x the upper limit of normal [ULN]) was 18.2% (42/231 patients) in the risk factor group and 5.8% (14/240 patients) in the non-risk factor group (OR 3.5; 95% CI 1.9-6.7; P < 0.001). Severe hepatotoxicity (transaminase > 10 x ULN) occurred in 6.9% (16/231) of the risk factor group and in 0.4% (1/240) (OR 17.7; 95% CI 2.3-135; P < 0.001) of the group without risk factors.
Conclusions: ATD-induced hepatitis is significantly more frequent and more severe in patients with hepatotoxicity risk factors.