A C-reactive Protein Level of 12 mg/L or Higher Defines Acute Severe Ulcerative Colitis

Traditionally, a cutoff of >30 mm/h for the erythrocyte sedimentation rate (ESR) constitutes severe disease in patients presenting with acute severe ulcerative colitis (ASUC). This study aimed to determine a corresponding C-reactive protein (CRP) value that reliably identifies patients with a severe flare of ulcerative colitis. 

The investigators analyzed prospectively collected data, including fecal calprotectin concentrations, Mayo endoscopic subscores, intravenous corticosteroid therapy failure rates, and colectomy-by-discharge rates, from 163 adult patients admitted to the hospital with ASUC as defined by Truelove and Witts criteria. They found that a CRP cutoff of ≥12 mg/L within 24 hours of presentation generated an 85% positive predictive value (PPV) with a sensitivity of 95% and an accuracy of 82% for having a paired ESR of >30 mm/h. There were no statistically significant differences between groups for the traditional ESR versus the new CRP-based criterion in the presenting fecal calprotectin, Mayo endoscopic subscores, or rates of intravenous corticosteroid therapy failure and colectomy-by-discharge. In addition, the CRP criterion of ≥12 mg/L identified an additional 15 patients (9%) who met the criteria for ASUC. Applying the CRP criterion of ≥12 mg/L to a validation cohort of 128 adults presenting with ASUC produced a PPV of 83% and a sensitivity of 94%.