Objectives: Immunomodulator (IM)-based monotherapy with thiopurines or methotrexate is being increasingly supplanted in the management of moderate-to-severe IBD by more efficacious biologic agents. However, given their low cost, IMs may still have a selective role in this setting.
Methods: We used a Canadian population-based dataset of persons with IBD spanning from 1996 until 2014 to assess the initiation and continued use of IM monotherapy, the incidence of outcomes associated with ineffectiveness (defined as IBD-related hospitalization, IBD-resective surgery, systemic corticosteroid (CS) use, or the need for biologic therapy), and the demographic and disease-related characteristics associated with persistence on IM monotherapy and IBD-associated adverse outcomes.
Results: There were 3312 persons diagnosed with IBD (1480 CD, 1832 ulcerative colitis (UC)) in the study period. The cumulative incidence of IM monotherapy use at 5 years was 46 % for CD and 24.9% for UC. Approximately one-third remained on IM monotherapy continuously for 5 years or more. Roughly three-quarters of IM users with a history of corticosteroid use had at least a 50% reduction in corticosteroid exposure in the year following IM initiation. Thirty-five percent of those with CD and 30% with UC had not developed evidence of therapeutic ineffectiveness within 5 years of IM initiation; people with no history of prior corticosteroid use, no IBD hospitalizations, and persons with CD initiating IM therapy after age 40 were less likely to have an episode of therapeutic ineffectiveness while on IM monotherapy CONCLUSIONS: Although the majority of persons who are initiated on IM monotherapy discontinue medications and/or have evidence of therapeutic ineffectiveness a significant minority remain free of these outcomes over many years of therapy.