P1287 Limited agreement between sCDAI and PGA disease activity scores in ileal vs colonic Crohn’s disease: retrospective analysis of the SPARC IBD longitudinal cohort

Abstract Background In Crohn’s disease (CD), disease location (ileal vs colonic disease) influences clinical presentation, disease course, and therapeutic response.1,2 The short Crohn’s Disease Activity Index (sCDAI)—comprising abdominal pain, diarrhoea frequency, and general well-being—is a widely used patient-reported measure of disease status. However, its weak correlation with objective measures of inflammation3 raises the question of whether it is influenced by disease location. The Physician global assessment (PGA) is a provider-reported summary measure, incorporating imaging and endoscopy data. This analysis evaluated the level of agreement between sCDAI and PGA scores by disease location in patients with CD. Methods Retrospective analysis of the SPARC IBD dataset,4 including US adults (≥18 years) with a diagnosis of CD enrolled between 8 November 2016 and 15 September 2025. Baseline clinical data were collected within 60 days of enrolment and included a median of 10 years of historical electronic medical record data. Agreement between baseline sCDAI and PGA scores was evaluated with the weighted κ statistic (95% CI). Remission status among patients in sCDAI remission (sCDAI < 150) at baseline was evaluated over 3 years of follow-up. Analyses were descriptive. Results A total of 4174 patients with CD (colonic-only, n = 559; ileal-only, n = 843; ileocolonic, n = 1939; unknown/missing disease location, n = 833) were included. Mean (SD) faecal calprotectin levels were lower for ileal vs colonic disease: 236.4 (345.1) µg/g vs 455.2 (846.1) µg/g. Stricturing disease (30.2% vs 8.1%) and surgeries (44.3% vs 19.5%) were higher for ileal vs colonic disease. A higher proportion of patients were in sCDAI remission vs PGA quiescence at baseline—colonic: 63.8% vs 51.9%; ileal: 60.2% vs 47.6%; ileocolonic: 58.0% vs 42.4% (Figure). The weighted κ statistic (95% CI) indicated fair agreement between sCDAI and PGA scores—overall: 0.34 (0.31, 0.37); colonic: 0.35 (0.28, 0.42); ileal: 0.30 (0.24, 0.36); ileocolonic: 0.36 (0.32, 0.39); all p < 0.001. Based on sCDAI, the relapse rate within 3 years was higher for ileal (27.6%) vs colonic (20.1%) disease (Table). Conclusion sCDAI and PGA scores showed limited agreement, with lowest concordance in ileal CD. A numerically higher proportion of patients met sCDAI remission than PGA quiescence, reflecting the incorporation of additional metrics into the PGA, such as imaging and endoscopy. The higher rate of stricturing disease, surgeries and sCDAI-based relapse in ileal vs colonic CD may partly account for the reduced sCDAI/PGA agreement in ileal CD. These findings support the integration of complementary measures alongside sCDAI to assess disease activity, particularly in ileal-dominant disease. References: 1. Lee HH et al. Clin Gastroenterol Hepatol. 2025:S1542-3565(25)00615-9. 2. Atreya R et al. Curr Res Pharmacol Drug Discov. 2022;3:100097. 3. Leake I. Nat Rev Gastroenterol Hepatol. 2013;10:564. 4. Raffals LE et al. Inflamm Bowel Dis. 2022;28:192–199. Conflict of interest: Dr. Cabrera-Moksnes, Claudia: AstraZeneca employee and shareholder Rhodes, Kirsty: AstraZeneca employee and shareholder Gairy, Kerry: AstraZeneca employee and shareholder Raman, Mekala R: AstraZeneca employee at the time the analysis was conducted Eberhardson, Michael: AstraZeneca employee and shareholder. Kostiuk, Benjamin: No conflict of interest Fehlmann, Tara: Employee of the Crohn’s & Colitis Foundation Marks, Daniel: Employee of AstraZeneca Lewis, James: Dr. Lewis consulted or served on an advisory board or data monitoring committee for Amgen, Crohn’s & Colitis Foundation, Eli Lilly and Company, Galapagos, Janssen Pharmaceuticals (Johnson & Johnson), Merck, Odyssey Therapeutics, Pfizer, Protagonist Therapeutics, Sanofi, and Spyre Pharmaceuticals. He has had research funding or in kind support from Nestle Health Science, Takeda, Janssen Pharmaceuticals, AbbVie and Eli Lilly. He has had educational grants from Janssen. He has performed legal work on behalf of manufacturers of generic ranitidine and 3M. He is an advisor to Chylometis in exchange for stock options and to Dark Canyon Labs in exchange for stock.