Magnetic resonance enterography, colonoscopy, and fecal calprotectin correlate in colonic Crohn's disease

Background: Fecal calprotectin (FCP), magnetic resonance enterography (MRE), and colonoscopy are complementary biometric tests that are used to assess patients with Crohn's Disease (CD). While prior studies have evaluated the association between combinations of these tests, no study has established a correlation between all three: FCP, MRE, and colonoscopy. We prospectively investigated if there is correlation between these three tests, which may result in improved clinical outcomes that can then be used to streamline patient monitoring and treatment modification. Methods: One hundred fifty-six patients with colonic CD were prospectively examined between March 2017 and December 2018. FCP levels, MRE, and colonoscopy were assessed in parallel on all 156 patients. Clinical CD activity was measured with the Crohn's Disease Activity Index (CDAI). CD activity with FCP was measured with a quantitative immunoassay. CD activity on MRE was measured with the Magnetic Resonance Index of Activity (MaRIA). CD activity on colonoscopy was measured with the Crohn's Disease Endoscopic Index of Severity (CDEIS). Results: One hundred twelve patients (72%) had active disease (Crohn's Disease Activity Index > 150) and 44 patients (28%) were in clinical remission disease (Crohn's Disease Activity Index < 150). FCP levels, MaRIA, and CDEIS are highly correlated with positive and significant Pearson and Spearman coefficients, respectively (P < 0.0001), in univariate analyses. Regression analysis (multivariate analyses) demonstrates significant, positive correlation between FCP and MaRIA (r = 1.07, P < 0.0001) and between FCP and CDEIS (r = 0.71, P = 0.03), and between. MaRIA and CDEIS (r = 0.63, P = 0.01). Conclusions: FCP levels significantly correlate with the degree of active inflammation in patients with colonic Crohn's Disease. Improved clinical results may be achieved by using a biometric strategy that incorporates FCP, colonoscopy, and MRE together. This strategy may in-turn be used in the future to streamline monitoring disease activity and adjustment of therapy to improve long term patient outcomes.