Deep ulcers are associated with increased C-reactive protein in active ulcerative colitis

Increased C-reactive protein (CRP) is used to diagnose and predict response to treatment in acute severe ulcerative colitis (UC).To investigate the connection between CRP elevation and deep ulcers in UC.Patients with active UC were enrolled in a multicenter prospective cohort and a retrospective cohort of consecutive patients undergoing colectomy from 2012 to 2019.Forty-one (9 (22%) with deep ulcers) patients were included in the prospective cohort: 4/5 (80%) patients with CRP > 100 mg/L, 2/10 (20%) patients with CRP between 30 and 100 mg/L and 3/26 (12%) patients with CRP < 30 mg/L had deep ulcers (p = 0.006). In the retrospective cohort [46 patients (31 (67%) with deep ulcers)], 14/14 (100%) patients with CRP > 100 mg/L, 11/17 (65%) patients with CRP between 30 and 100 mg/l and 6/15 (40%) patients with CRP < 30 mg/L had deep ulcers (p = 0.001). Positive predictive value of CRP > 100 mg/l for presence of deep ulcers was 80% and 100% in both cohorts, respectively.CRP elevation is a robust surrogate marker for presence of deep ulcers in UC. Elevated CRP or presence of deep ulcers could influence the choice of medical therapy in acute severe UC.