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

Atia, O.(1);Goren, I.(2)*;Sharar Fischler, T.(2);Loewenberg Weisband, Y.(3);Greenfeld, S.(4);Kariv, R.(5);Ledderman, N.(6);Matz, E.(7);Magen Rimon, R.(8);Dotan, I.(2);Turner, D.(1);Yanai, H.(2);

(1)Shaare Zedek Medical Center, Juliet Keidan Institute of Pediatric Gastroenterology Hepatology and Nutrition, Jerusalem, Israel;(2)Rabin Medical Center, Division of Gastroenterology, Petah Tikva, Israel;(3)Clalit Health Services, Clalit Research Institute, Tel Aviv, Israel;(4)Maccabi health services, Maccabi health services, Tel Aviv, Israel;(5)Maccabi Healthcare Services, Gastroenterology, Tel Aviv, Israel;(6)Meuhedet Health Services, Meuhedet Health Services, Tel Aviv, Israel;(7)Leumit Health Services, Leumit Health Services, Tel Aviv, Israel;(8)Rambam Medical Center, Pediatric Gastroenterology & Nutrition institute, Haifa, Israel;


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.


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.


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.


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.