Transmural Healing Assessed by Combination of Fecal Calprotectin and Intestinal Ultrasonography Is Associated With Reduced Risk of Bowel Damage Progression in Patients With Crohn's Disease

Abstract

Background: Fecal calprotectin (Fcal) and intestinal ultrasonography (IUS) could be used as noninvasive tools to monitor mucosal and transmural healing, respectively, in Crohn's disease (CD). We assessed the agreement between Fcal and IUS to detect active CD and investigated their complementary to predict long-term CD outcomes.

Methods: In this prospective study, we consecutively included CD patients with concomitant IUS and Fcal testing within 7 days. Patients were divided into 4 groups: Transmural healing (TH; both normal), IUS healing (Fcal > 100 µg/g but normal IUS), biochemical remission reflecting mucosal healing (MH; Fcal < 100 µg/g but abnormal IUS), and no healing (abnormal Fcal and IUS). The primary endpoint was active CD. The secondary endpoints were time to bowel damage progression, time to relapse-related drug discontinuation, and patients' acceptability (10-points acceptability numerical scale).

Results: Among the included 112 patients, 44.6% (50/112), 12.5% (14/112),16.1% (18/112), and 26.8% (30/122) achieved TH, IUS healing, biochemical remission, and no healing, respectively. The agreement between IUS and Fcal to detect an active CD was poor (71.4%, κ-coefficient = 0.41 ± 0.09). Transmural healing was associated with a reduced risk of bowel damage progression compared to no healing (P < .0001) contrary to IUS healing (P = .15) or biochemical remission (P = .84). Transmural healing was associated with a lower risk of relapse-related drug discontinuation than MH (hazard ratio [HR] = 0.09 [0.02-0.45], P = .003), IUS healing (HR = 0.10 [0.02-0.60], P = .001), or no healing (HR = 0.09 [0.018-0.04], P = .002). IUS was better accepted than Fcal testing (9.6 ± 0.8 vs 7.9 ± 2.3; P < .0001, 10-points range-acceptability numerical scale).

Conclusions: Transmural healing, evaluated by the combination of noninvasive and well-accepted tools such as Fcal and IUS, is associated with improved long-term outcomes and could be used to monitor patients with CD in daily practice.

Keywords: Crohn’s disease; bowel damage; fecal calprotectin; intestinal ultrasound; monitoring; transmural healing.