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

Background: Increased C-reactive protein (CRP) is used to diagnose and predict response to treatment in acute severe ulcerative colitis (UC).

Aims: To investigate the connection between CRP elevation and deep ulcers in UC.

Methods: Patients with active UC were enrolled in a multicenter prospective cohort and a retrospective cohort of consecutive patients undergoing colectomy from 2012 to 2019.

Results: 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.

Conclusions: 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.