Anti-tuberculous drug induced hepatitis in Sri Lankan patients

Abstract

OBJECTIVE: To determine the incidence and risk factors of anti-TB drug induced hepatitis (AIH) in Sri Lankan patients and to address management options. DESIGN, SETTING AND METHODS: 783 patients with a confirmed diagnosis of TB who presented to a unit at Chest Hospital, Welisara from April 2001 to April 2002 were recruited for a follow up study. WHO category 1 for new and category 2 for re-treatment cases was commenced using single drug formulations. Doses were based on three weight bands. AIH was diagnosed when patients complained of decreased appetite, nausea/vomiting and elevated serum biliru&n (SB) l.lmg/dl or elevated serum alanine transferase (ALT) 3 times upper limit of normal (ULN). Results: 74 patients (9.5%) out of 783 enrolled patients developed AIH; the majority (58%) developing AIH within the first two weeks of the intensive phase of treatment. AIH was commoner among patients over 60 years (p=0.018), with pulmonary TB (p=0.028) and weighing 33-35 kg (p=0.004). Using regression analysis, age, weight and rifampicin overdosage were significant predictors of AIH. Of the 74 AIH patients, standard treatment was restarted in 60 and treatment was modified in six; two defaulted and six died. Conclusions: Incidence of AIH among Sri Lankan patients is 9.5%. They develop symptoms of hepatitis when ALT levels rise to three times the ULN lowering the threshold for diagnosis of AIH. Old age, 33-55 kg weight band and rifampicin over dosage are risk factors for AIH. Majority (81%) of AIH patients could be restarted on standard treatment.