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.