Natural history and outcomes in drug induced autoimmune hepatitis

Aim: Drug-induced autoimmune hepatitis (DIAIH) remains poorly characterized. Our aim was to assess natural history and outcomes in DIAIH. Methods: This was a retrospective cohort study. Results: Eighty-two patients with autoimmune hepatitis (AIH) were identified, 11 (13.4%) with DIAIH, implicated drugs being nitrofurantoin (n?=?4), statins (n?=?4), herbal remedies (n?=?2) and diclofenac (n?=?1). Female sex, acute onset, elevated serum globulins/immunoglobulin G, fibrosis stage (Ishak), cirrhosis at onset, moderate–severe portal inflammation, interface and lobular hepatitis, remission, relapse and poor outcome were similar in those with DIAIH and AIH (P?>?0.05). The former were however more likely to be aged 60?years or more and take longer to relapse on immunosuppression discontinuation (P?=?<0.05). On Kaplan–Meier analysis, probability of poor outcome was similar in those with DIAIH and AIH (log–rank test, 0.339). On comparing those with (n?=?4) and without nitrofurantoin (n?=?7) DIAIH, the former were older, had longer duration of drug use prior to DIAIH diagnosis, higher fibrosis stage and were less likely to relapse upon immunosuppression discontinuation. Conclusion: Approximately 15% of patients with AIH have DIAIH with similar outcomes, although the latter are older with a propensity for late relapse, mandating long-term follow up.