P0373Factors Associated with a Complicated Behavior or Diagnostic Delay in Crohn’s Disease: A Prospective Multicenter French and Belgian Cohort of Newly Diagnosed Patients

Abstract Background Despite diagnostic advances, one-third of Crohn’s disease (CD) patients still present with complicated behavior at diagnosis. Delayed diagnosis, often related to nonspecific symptoms or socio-demographic factors, may contribute to this 1. We aimed to identify factors linked to delayed diagnosis or complicated CD. Methods We conducted a prospective multicenter observational study in France and Belgium (April 2024 - December 2025) including consecutive CD patients (≥18 years) diagnosed within the last 12 months. Patients and gastroenterologists completed questionnaires on clinical, socio-demographic, socio-economic deprivation assessed by the EPICES score (French individual index of deprivation), and healthcare pathway data. Late diagnosis was defined as 12 months from symptom onset. Univariate analyses compared inflammatory (B1) vs complicated (Stricturing = B2/ Fistulizing = B3) behavior and delayed (12 months) vs timely (12 months) diagnosis. Multivariate analyses will follow. Results Across 61 centers, 743 patients were enrolled. We present findings from the first 316 included. Forty-nine percent were female; median age was 30 years 23–43. Disease location was ileal (48%), colonic (18%), or ileocolonic (34%). At diagnosis, 63% had B1 and 37% B2/B3 behavior; 24% had a delayed diagnosis. Complicated CD was more frequent in male patients (61% vs 46%;p = 0.010), in case of ileal location (58% vs 42%; p = 0.010) and hospitalization at diagnosis (71% vs 44%;p0.001). B1 behavior was more common in female patients (54% vs 39%; p = 0,010), patients having children (46% vs 33%;p = 0.033), family history of IBD (27% vs 16%; p = 0.037), and was associated with misdiagnosis (44% vs 32%;p = 0.,030), ≥3 General Practitioners (GP) consultations prior to diagnosis (45% vs 24%;p0.,001), diarrhea (42% vs 12%;p0.001) and presence of at least one red flag (nocturnal diarrhea, prolonged diarrhea, rectal bleeding, or weight loss) (93% vs 74%; p 0.001). Diagnostic delay was associated with ≥3 GP consults (59% vs 31%;p0.001), misdiagnosis (64% vs 32%;p0.001), 4-week wait for gastroenterologist visit (58% vs 35%; p 0.001), and use of complementary medicine (38% vs 21%;p0.007). No association was found with gender, age, red flags, EPICES score and disease location or behavior. Conclusion In this large cohort of CD patients, B1 forms seemed to be initially misdiagnosed for irritable bowel syndrome-diarrhea, leading to a prolonged diagnostic journey before gastroenterology referral, whereas complicated forms (B2/B3) may have evolved silently before presenting with abrupt and severe manifestations prompting immediate evaluation. Diagnostic delays were mainly driven by factors related to the healthcare pathway rather than by deprivation or disease behavior. Reference: 1. Souaid C, Fares E, Primard P, Macaigne G, El Hajj W, Nahon S. A review investigating delays in Crohn’s disease diagnosis. Clin Res Hepatol Gastroenterol. 2025;49(1):102500. doi:10.1016/j.clinre.2024.102500 Conflict of interest: Dr. Souaid, Christophe: No conflict of interest Flamant, Mathurin: No conflict of interest Bozon, Anne: No conflict of interest Nancey, Stéphane: board membership and lecturing fees from Abbvie, Takeda, Celltrion Healthcare, Pfizer, Galapagos, Johnson & Jonshon, Lilly, Fresenius, Amgen, Medac, MSD. Caron, Bénédicte: No conflict of interest Blanc, Pierre: No conflict of interest Buisson, Anthony: Grant: Abbvie, Celltrion, Pfizer and Takeda Personal Fees: Abbvie, Amgen, Arena, Biogen, Celltrion, Ferring, Janssen, MSD, Pfizer, Roche, Sanofi-Aventis, Takeda, Tillotts, Vifor Pharma, Richard, Nicolas: Lecture/consultant fees from AbbVie, Amgen, Celltrion, Ferring, Janssen, Lilly, Sandoz and Takeda. Barrau, Mathilde: No conflict of interest Faure, Patrick: No conflict of interest Nachury, Maria: Abbvie, Alfa Sigma, Biosynex, Celltrion, Galapagos, Janssen, Lilly, MSD, Pfizer, Takeda Allez, Matthieu: Grant: Janssen, Genentech/Roche, Takeda Personal Fees: Abbvie, Amgen, Astra-Zeneca, Biogen, Boehringer-Ingelheim, Bristol Myers Squibb, Celgene, Celltrion, Ferring, Galapagos, Genentech, Gilead, IQVIA, Janssen, Novartis, Pfizer, Spyre therapeutics, Roche, Takeda, Tillots Fumery, Mathurin: Grant: Pfizer Personal Fees: Abbvie, Janssen, Takeda, MSD, Biogen, Amgen, Sandoz, Fresenius, Gilead, Celgene, Galapagos, Mylan, Tillots, Ferring, Pfizer, Hospira, CTMA, Boehringer, Lilly, Arena Non-financial Support: Abbvie, Janssen, Takeda, MSD, Galapagos, Ferring, Pfizer Mathieu, Nicolas: Payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events: Abbvie, Alfa sigma,Biosynex, Celltrion, Janssen, Lilly, Pfizer, Takeda: Speakers fees payments Support for attending meetings and/or travel: Abbvie, Celltrion, Janssen, Lilly, Pfizer, Takeda Participation on a Data Safety Monitoring Board or Advisory Board: Abbvie, Alfa sigma, Celltrion, Janssen, Lilly, Medtronic, Pfizer, Takeda Clairet, Valentine: No conflict of interest Charkaoui, Maeva: No conflict of interest Caillo, Ludovic: Abbvie, Amgen, Celltrion, Ferring, Fresenius, Lilly, Jonhson&Jonhson, MSD, Pfizer, Takeda, Sandoz Laharie, David: Personal Fees: Board, consulting and lecture fees from Abbvie, Alfasigma, Amgen, Biocon, Celltrion, Ferring, Fresenius-Kabi, Johnson & Johnson, Lilly, MSD, Pfizer, Sandoz and Takeda Uzzan, Mathieu: Grant: ECCO-IOIBD, Fondation pour la Recherche Medicale (FRM), SNFGE Personal Fees: Abbvie, Takeda, Celltrion, Janssen, Amgen, Alfasigma, Pfizer Etienney, Isabelle: takeda Locher, Christophe: No conflict of interest Guillo, Lucas: No conflict of interest Reenaers, Catherine: Grant: Ferring, Janssen, Takeda, Fresenius, Biogen Personal Fees: Ferring, Janssen, Takeda, Fresenius, Abbvie, Galapagos, Pfizer, Celltrion, Thermofisher, BMS, Lilly, Thermofisher Nuzzo, Alexandre: No conflict of interest Vidon, Mathias: No conflict of interest Gouynou, Célia: No conflict of interest Kirchgesner, Julien: Lecture fees and/or consulting fees from from Abbvie, Amgen, Astrazeneca, Celltrion, Galapagos, Janssen, Lilly, MSD, Takeda, Tillots, Pfizer. Viennot, Stéphanie: No conflict of interest Pelletier, Anne-Laure: received lecture/consultant fees from Janssen,Pfizer and Novartis Liefferinckx, Claire: Consultancy/speaker fees: Takeda, Janssen, Abbvie, Alfasigma, Celltrion Le Gall, Guillaume: No conflict of interest Paupard, Thierry: No conflict of interest Cavicchi, Maryan Nicolas: M.C.: Consultant for JOHNSON & JOHNSON, ABBVIE, TAKEDA and MSD Honoraria for lectures, presentations, speakers for MSD, LILLY, ABBVIE, AMGEN, TAKEDA, PFIZER, MYLAN and TILLOTS Support for attending meetings from JOHNSON & JOHNSON, ABBVIE, FERRING, TAKEDA and MSD Board for JOHNSON & JOHNSON, ABBVIE, PFIZER and LILLY Receipt of equipment and materials from CELTRION and BIOSYNEX Fathallah, Nadia: Grant: A. Legrand AbbVie Amgen Biolitec Brothier FCare Systems Janssen Sandoz Takeda THD Lab Tillotts Pharma Favier, Laurie: No conflict of interest Skinazi, Florence: No conflict of interest Le Berre, Catherine: Abbvie, Amgen, Celltrion, Ferring, Fresenius Kabi, Galapagos, Gielad, Janssen, Lilly, MSD, Nordic Pharma, Pfizer, Sandoz, Takeda. Del Tedesco, Emilie: Abbvie, Sanofi, Ferring, Pfizer, Janssen, Takeda, Mylan, Viatris, Norgine, Lilly, Biogen, Mayoly,Gilead, Amgen et Celltrion Renaud, Laurence: No conflict of interest Nahon, Stéphane: No conflict of interest</jats: