Lowering the C‐Reactive Protein ( <scp>CRP</scp> ) Threshold Improves Risk Stratification in Acute Ulcerative Colitis: A Propensity‐Matched Analysis

BACKGROUND: Real-world data demonstrate that patients hospitalised with non-acute severe UC (NASUC) experience intravenous corticosteroid (IVCS) failure rates approaching those of ASUC, yet no dedicated management guidelines exist. AIMS: We aimed to determine whether inpatient medical therapy and colectomy risk differ between TWC-positive ASUC, compared to hospitalised patients who did not meet TWC (NASUC), and evaluate if a reduced CRP threshold (≥ 12 mg/L) improves case capture of high-risk patients. METHODS: We analysed 503 consecutive acute UC admissions to a tertiary IBD centre (2015-2024). Patients not meeting TWC for ASUC were classified as NASUC. Propensity score matching (PSM) compared colectomy risk between ASUC and NASUC after adjustment for gender, endoscopic severity, disease extent and therapy on admission. RESULTS: A total of 145 (29%) acute UC admissions did not meet TWC for ASUC. The predominant NASUC phenotype was stool frequency ≥ 6/24 h without systemic toxicity (77%). Lowering the CRP threshold to ≥ 12 mg/L would have reclassified 26% of NASUC patients as ASUC, capturing 43% (6/14) of patients who required colectomy within 1-year. After PSM, there was no significant difference in colectomy between ASUC and NASUC at 30-days (9% vs. 5%, p = 0.367), 90-days (11% vs. 5%, p = 0.158) or 1-year (18% vs. 13%, p = 0.479) and until last follow-up (p = 0.77). CONCLUSION: NASUC is not a benign clinical entity. Colectomy risk were comparable between ASUC and NASUC inpatients when matched for objective disease severity and treatment exposure. A reduced CRP threshold (≥ 12 mg/L) improves identification of high-risk patients currently missed by the standard TWC.