P467 5-ASA is not superior to no-maintenance in patients with newly diagnosed Crohn’s disease - a nationwide cohort from the epi-IIRN

Abstract

Abstract Background 5-aminosalicylates (5-ASA) are widely used in Crohn's disease (CD) despite guidelines advising otherwise. In this nationwide study, we aimed to assess the outcomes of first-line 5-ASA-maintenance therapy (5-ASA-MT) compared with no-maintenance treatment (no-MT) in patients with newly diagnosed CD. Methods We utilized data from the epi-IIRN cohort, including all patients with CD diagnosed in Israel between 2005-2020. Outcomes included therapeutic failure, hospitalization, surgeries, steroid dependency, escalation to biologics, and 5-ASA-related adverse events. Propensity-score (PS) matching was utilized to compare outcomes in the 5-ASA-MT vs. no-MT groups. Results Of the 19,264 patients diagnosed with CD, 3,027 (16%) received first-line 5-ASA-MT and 5,583 (29%) received no-MT. Both strategies declined over the years; 5-ASA-MT from 21% in 2005 to 11% in 2019 (p<0.001) and no-MT from 36% to 23% (p<0.001). The probability of maintaining therapy at one, three, and five years from diagnosis: 5-ASA-MT- 78%, 57%, and 47%, no-MT- 76%, 49%, and 38%, respectively (both p<0.001). PS analysis successfully matched 1,993 pairs of treated and untreated patients and demonstrated comparable outcomes of time to: biologic (p=0.2), steroid-dependency (p=0.9), hospitalization (p=0.5), and CD-related surgery (p=0.1). On the other hand, rates of acute kidney injury (5.2% vs. 3.3%; p<0.001) and pancreatitis (2.4% vs. 1.8%; p=0.03) were higher in the 5-ASA-MT group. Conclusion First-line 5-ASA-monotherapy was not superior to no-MT but associated with a slightly higher rate of adverse events, while both strategies have declined over the years. These findings suggest that a subset of patients with mild CD may be offered a watchful waiting approach.