P051 Identifying High-Risk Patients With Acute Severe Ulcerative Colitis: Is the ACE Index Useful?

BACKGROUND: Treatment delay in patients admitted with acute severe ulcerative colitis (ASUC) are associated with increased mortality. Therefore, it is essential to identify on admission patients at high-risk of steroid nonresponse who may benefit from earlier second-line treatment or surgical intervention. Recently, the ACE index was developed and includes 3 variables at admission: C-reactive protein (CRP) ≥50mg/dL, albumin ≤30g/L and endoscopic severity (Mayo endoscopic score=3), and ranges between 0-3 points. An index of 3 has been shown to be useful to identify patients with acute ulcerative colitis with high-risk of steroid nonresponse. OBJECTIVES: To assess the ACE index performance in predicting steroids response in ASUC. METHODS: Retrospective study including consecutive admissions for ASUC according to Truelove and Witts definition between January 2005 and December 2020. The ACE index was calculated and its accuracy for predicting response to steroids on admission in ASUC was assessed through the area under the curve (AUC). RESULTS: Sixty-five patients were included of whom 78.5% responded to steroids. Mean CRP (p = 0.01), albumin (p=0.02) and endoscopic severity score (p < 0.001) at admission were significantly different between responders and nonresponders, as opposed to Ulcerative Colitis Endoscopic Index of Severity (UCEIS) score (p = 0.32). Median ACE index was 2. The ACE index was a predictor of steroids response (AUC 0.789; p = 0.001); 50.0% of patients with an index of 3 did not respond to steroids, and 86.3% of patients with an index inferior to 3 responded to steroids (positive predictive value 50.0%; negative predictive value of 86.3%). CONCLUSION: The ACE index is an accurate predictor of steroids response on admission in ASUC. However, in our study, the ACE index doesn´t discriminate whose high-risk patients would benefit from earlier therapeutic escalation, since only 50.0% of patients with an index of 3 did not respond to steroids.