Continuing or stopping 5-aminosalicylates in patients with inflammatory bowel disease on anti-TNF therapy: A nationwide population-based study.

Background: The impact of continuing or stopping 5-aminosalicylates (5-ASA) after commencing anti-tumour necrosis factor (anti-TNF) therapy in patients with inflammatory bowel disease (IBD) remains unclear.

Aims: To compare the outcomes of patients with IBD who stopped or continued 5-ASA after starting anti-TNF therapy.

Methods: We analysed data from the Korean National Health Insurance claims database between 2007 and 2020. We compared the clinical outcomes of patients who stopped or continued 5-ASA within 90 days of anti-TNF initiation. The primary outcome was any adverse clinical event defined as a composite of new corticosteroid use, IBD-related hospitalisation, or intestinal surgery.

Results: Among 7442 patients included for analysis (4479 [60.2%] with Crohn's disease [CD] and 2963 [39.8%] with ulcerative colitis [UC]), 1037 (13.9%) discontinued 5-ASA within 90 days of starting anti-TNF therapy. During a median 4.3-year follow-up, discontinuation of 5-ASA was not associated with an increased risk of adverse clinical events (adjusted hazard ratio 1.01, 95% confidence interval 0.93-1.10). The cumulative incidence of each adverse clinical event and the composite outcome were not significantly different between groups (all, p > 0.05). Additionally, separate analyses in CD and UC cohorts revealed no differences in adverse clinical outcomes between the 5-ASA continuation and discontinuation groups. Subgroup analyses by presumed risk factors for disease relapse showed no significant differences in the risk of adverse events between groups.

Conclusions: In this nationwide population-based study, discontinuing 5-ASA after starting anti-TNF therapy was not associated with an increased risk of adverse events in patients with IBD.