P404 Stopping 5-aminosalicylates in Crohn’s disease patients starting biologic therapy does not increase the risk of adverse clinical outcomes: analysis of two nationwide population-based cohorts

Abstract

Background: The impact of discontinuing 5-aminosalycilates (5-ASA) in Crohn's disease (CD) patients who initiate anti-tumour necrosis factor alpha (anti-TNF) biologics is unknown. We aimed to compare clinical outcomes in CD patients already on 5-ASA who started anti-TNF and then either stopped or continued 5-ASA. Method(s): We analysed two national databases: the USA (U.S.) Truven MarketScan health claims database and the Denmark health registers. CD patients who started anti-TNF after having been on oral 5-ASA for at least 90 days were included. Patients were classified as stopping 5-ASA if therapy was discontinued within 90 days of starting anti-TNF. Our primary outcome was any adverse clinical event defined as a composite of new corticosteroid use, CD-related hospitalisation or surgery. We performed Kaplan-Meier analyses and multivariable Cox regression models controlling for age, gender, duration of 5-ASA treatment before anti-TNF initiation, prior CD-related surgery, disease duration (Danish database only) and healthcare utilisation (corticosteroid use, hospitalisations and emergency department visits in year prior to anti-TNF). Adjusted hazard ratios (aHR) with 95% confidence intervals (95% CI) are reported comparing stopping 5-ASA with continuing 5-ASA. Result(s): A total of 3,178 CD patients were included (2,960 USA and 218 Denmark). 1,044 patients in the US cohort and 106 patients in the Danish cohort stopped 5-ASA after starting anti-TNF. In both cohorts, cumulative rates of the adverse clinical events composite primary outcome were similar when comparing those who stopped vs. those who continued 5-ASA (Figures 1 and 2). In multivariable analysis, stopping 5-ASA after initiating anti-TNF was not associated with an increased risk of adverse clinical events in the U.S. cohort (aHR 0.89, 95% CI 0.77-1.03, p = 0.13) nor in the Danish cohort (aHR 1.13, 95% CI 0.68-1.87, p = 0.63). Results were similar in sensitivity analyses investigating concomitant immunomodulator use and duration of 5-ASA treatment before initiating anti-TNF. Conclusion(s): In two national databases, stopping 5-ASA in CD patients starting anti-TNF therapy did not increase the risk of adverse clinical events. These results should be validated in a prospective clinical trial. (Figure Presented).