P0326Disease Behaviour Progression and Associated Factors in Crohn’s Disease Patients: the Nationwide Inception Cohort Study of Crohn’s Disease (iCREST-CD)

Abstract Background Despite advances in biologic therapy, progression of Crohn’s disease (CD) behaviour remains a major clinical challenge, as it can lead to complications and affect long-term outcomes 1. This study aimed to evaluate the frequency of disease behaviour progression (DBP) and its associated factors, based on a Japanese nationwide inception cohort. Methods Patients diagnosed with CD on or after June 2016 were enrolled between 2018 and 2020 and followed prospectively for up to 4 years after consent, with retrospective data collected from diagnosis. Disease behaviour per Montreal classification: B1 (non-stricturing/non-penetrating), B2 (stricturing), B3 (penetrating); DBP = B1→B2/B3 or B2→B3. Location: L1 (ileal), L2 (colonic), L3 (ileocolonic) 2. Analyses included Kaplan–Meier estimates and logistic regression. Step-up therapy was defined as initiation of biologics after prior use of corticosteroids (CS), whereas top-down strategy indicated biologic initiation without prior CS exposure. Surgery was defined as intestinal resection or strictureplasty. Results Among 588 patients with B1/B2 at diagnosis, 76 (12.9%) patients experienced DBP during follow-up. The proportions of patients who experienced DBP by baseline disease location were L1: 8.9% (11/123), L2: 9.7% (10/103), and L3: 15.3% (54/352), with the highest rate in L3. Patients with DBP had numerically higher baseline HBI scores and CRP levels (HBI: 6.2 vs 4.8; CRP: 31.6 vs 26.2 mg/L). Delayed biologic initiation (≥6 months post-diagnosis) was associated with an increased risk of DBP (OR 1.75, 95% CI 1.04–2.95, p = 0.017), whereas a top-down strategy reduced the risk (OR 0.55, 95% CI 0.33–0.94, p = 0.013). Perianal disease at diagnosis was not associated with DBP (OR 1.01, 95% CI 0.63–1.63, p = 0.971) Table 1. At 48 months, surgery rates were L1: 21.5%, L2: 6.4%, and L3: 14.0%, with L1 showing the highest risk despite lower DBP rates, and L3 having the next highest surgery rate Figure 1. Conclusion DBP occurred in approximately 13% of patients during the observational period. Delayed biologic initiation and step-up therapy were significant risk factors, whereas a top-down strategy was protective. Although L3 was associated with the highest progression rate, patients with L1 had the highest risk of surgery; however, the absolute surgery rate for L1 (21.5%) was substantially lower than previously reported 4,5. This reduction could reflect trends toward advanced therapy and more frequent use of top-down strategies in Japanese clinical practice. These findings provide real-world evidence to inform treatment strategies for CD 5. References: 1. Cosnes J, et al. Factors affecting the long-term outcome of Crohn’s disease. Inflamm Bowel Dis. 2002;8(4):244–250. 2. Louis E, et al. The Montreal classification of inflammatory bowel disease: controversies, consensus, and implications. Gut. 2005;54(6):693–700. 3. Gonczi L, et al. Long-term disease progression and resective surgery rates in Crohn’s disease over different therapeutic eras – a population-based study from western Hungary between 1977–2020, data from the Veszprem county cohort. J Crohns Colitis. 2023;17(Suppl 1):i127–i128. 4. Bernstein CN, et al. Crohn’s Disease Phenotypes and Associations With Comorbidities, Surgery Risk, Medications and Nonmedication Approaches: The MAGIC in IMAGINE Study. Inflamm Bowel Dis. 2025;31(1):113–122. 5. Gordon H, et al. ECCO Guidelines on Therapeutics in Crohn’s Disease: Medical Treatment. J Crohns Colitis. 2024;18(10):1531–1555. Conflict of interest: Matsuoka, Katsuyoshi: Grants: AbbVie, JIMRO, Mochida, Nippon Kayaku Consulting: Janssen, Takeda, EA Pharma, Mochida, Eli Lilly, Mitsubishi Tanabe Pharma, AbbVie, Pfizer, Gilead, Bristol-Myers Squibb Lectures: Janssen, Takeda, EA Pharma, Mochida, Zeria, Nippon Kayaku, Eli Lilly, Mitsubishi Tanabe Pharma, AbbVie, Pfizer, Kyorin, Kissei, Gilead, Bristol-Myers Squibb Fujii, Toshimitsu: Grants Janssen Pharmaceutical K.K, AbbVie, Boehringer Ingelheim, Bristol-Myers Squibb, EA, Kissei, Takeda, Alfresa Corporation, Celgene, Eli Lilly, Gilead Sciences, Mebix, Sanofi Personal Fees Payment for lectures/presentations: Janssen Pharmaceutical K.K, AbbVie, Boehringer Ingelheim, Bristol-Myers Squibb, EA, Kissei, Kyorin, Mitsubishi Tanabe, Mochida, Nichiiko, Nippon Kayaku, Pfizer, Takeda, Taiho, Zeria Okamoto, Ryuichi: Grants Mitsubishi Tanabe Zeria Mochida Takeda Yamada, Akihiro: Grants AbbVie GK Mitsubishi Tanabe EA Mochida Kunisaki, Reiko: Grants: Janssen, AbbVie GK, EA, Kissei, Mitsubishi Tanabe, Takeda, Zeria, Ajinomoto, Eli Lilly, Pfizer Lectures: Janssen, AbbVie GK, EA, Kissei, Kyorin, Nippon Kayaku, Mitsubishi Tanabe, Takeda, Zeria Matsuura, Minoru: Lectures: Janssen, Mitsubishi Tanabe, AbbVie GK, Takeda, Kyorin, Mochida, Viatris, Sandoz, Nippon Kayaku, JIMRO, EA, Zeria Watanabe, Kenji: Grant) Research group of intractable IBD, the Ministry of Health, Labor and Welfare in Japan Japanese Society of Gastroenterology Honoraria) Takeda Pharmaceutical Co., Ltd. AbbVie GK EA Pharma Co., Ltd. Mitsubishi Tanabe Pharma Corporation Mochida Pharmaceutical Co., Ltd. JIMRO Co., Ltd. Advisory Board) Takeda Pharmaceutical Co., Ltd. Shiga, Hisashi: Grants: Janssen Lectures: Mitsubishi Tanabe, Gilead, EA Pharma, Mochida, Takeda, AbbVie, Janssen, Pfizer Takatsu, Noritaka: NA Bamba, Shigeki: Grants: AbbVie GK Lectures: AbbVie GK, Mitsubishi Tanabe, Kyorin, Janssen, Mochida, EA Mikami, Yohei: Grants: Janssen Yamamoto, Takayuki: Grants: Janssen Shimoyama, Takahiro: NA Motoya, Satoshi: Grants: AbbVie GK, Eli Lilly, Takeda, Janssen, Pfizer, EA Lectures: Mitsubishi Tanabe, AbbVie GK, Mochida, Gilead, Janssen Torisu, Takehiro: NA Kobayashi, Taku: Grant: AbbVie, Alfresa Pharma, Bristol Myers Squibb, Celtrion, EA Pharma, Gilead Sciences, Kyorin Pharmaceutical, Miyarisan, Mochida Pharmaceutical, Nippon Kayaku, Otsuka Holdings, Pfizer, Sekisui Medical, Takeda, Zeria Pharmaceutical Personal Fees: AbbVie, Alfresa Pharma, Alimentiv, Bristol Myers Squibb, Celltrion, Covidien, EA Pharma, Eli Lilly, Ferring Pharmaceuticals, Galapagos, Gilead Sciences, Janssen, JIMRO, Kissei Pharmaceutical, Kyorin Pharmaceutical, Mitsubishi Tanabe Pharma, Mochida Pharmaceutical, MSD, Nippon Kayaku, Pfizer, Sekisui Medical, Takeda Pharmaceutical, Zeria Pharmaceutical Ohmiya, Naoki: Grants: AbbVie GK, Daiichi Sankyo, Bristol-Myers Squibb, Takeda, Eli Lilly, Mitsubishi Tanabe, Nippon Kayaku Lectures: EA, Janssen Saruta, Masayuki: Grants: Mochida, Zeria, EA Pharma, Kissei, EPS Lectures: AbbVie GK, Janssen, Mitsubishi Tanabe, Takeda, EA Pharma, Gilead Matsuda, Koichiro: Lectures: Janssen, Mitsubishi Tanabe, Takeda, AbbVie, Eli Lilly Advisory Board: Janssen Matsumoto, Takayuki: Grants: Janssen, Mitsubishi Tanabe Lectures: Janssen, Mitsubishi Tanabe, EA Pharma, AbbVie, Takeda Nakase, Hiroshi: AbbVie GK., Kyorin Pharmaceutical Co.,Ltd., Mitsubishi Tanabe Pharma Corporation, Janssen Pharmaceutical K.K, Takeda Pharmaceutical Co.,Ltd., Pfizer Inc, EA Pharma Co.,Ltd., Mochida Pharmaceutical Co.,Ltd., JIMRO Co.,Ltd., Bristol-Myers Squibb Company., MIYARISAN Pharmaceutical Co., Ltd., as well as grants for commissioned/joint research from Hoya Group Pentax Medical. Maemoto, Atsuo: Grants: AbbVie GK, Gilead, Galapagos, Janssen, Eli Lilly, Takeda, Pfizer, Mitsubishi Tanabe Lectures: Janssen, JIMRO Shinzaki, Shinichiro: Grants: Sekisui Medical, Janssen, AbbVie, IQVIA Consulting: AbbVie, G