Factors influencing physician decisions to discontinue treatment after onset of liver dysfunction: analysis of an all-case post-marketing surveillance study of iguratimod.

Adverse drug reactions (ADRs) related to liver dysfunction are a common problem in patients with rheumatoid arthritis (RA) receiving iguratimod, but which patient subgroups go on to discontinue iguratimod treatment is unclear. A analysis of a post-marketing surveillance study was performed to investigate factors influencing treatment continuation after the onset of liver dysfunction. Types of ADR were compared between patients in whom iguratimod treatment was discontinued or continued in accordance with the judgment of the patient's physician after the patient developed liver dysfunction as an ADR. Stepwise logistic regression analysis was also conducted to investigate factors associated with treatment discontinuation. The multivariate analysis found that concomitant use of methotrexate (MTX) at >8 mg/week (vs. no use) was associated with a significantly lower risk of discontinuation (OR: 0.136; 95%CI: 0.030-0.620), and previous treatment with MTX (vs. no use) was associated with a significantly higher discontinuation risk (OR: 4.045; 95%CI: 1.098-14.908). Although concomitant use of MTX during iguratimod treatment does not appear to influence treatment discontinuation due to abnormal liver function, liver function tests are of importance to continued treatment in patients receiving iguratimod who have a history of MTX use.