Association Between Level of Fecal Calprotectin and Progression of Crohn's Disease.

Background & Aims: Mucosal healing is associated with improved outcomes in patients with Crohn's disease (CD), but assessment typically requires ileocolonoscopy. Calprotectin can be measured in fecal samples to determine luminal disease activity in place of endoscopy-this measurement is an important component of the treat-to-target strategy. We investigated whether levels of fecal calprotectin are associated with subsequent CD progression.

Methods: We performed a retrospective study of 918 patients with CD (4218 patient-years of follow-up evaluation; median, 50.6 mo; interquartile range [IQR], 32.8-76.0 mo) managed at a tertiary medical center in Edinburgh, United Kingdom, from 2003 through 2015. Patients were included if they had 1 or more fecal calprotectin measurements made 3 months or more after their diagnosis. We collected clinical data and fecal calprotectin measurements and analyzed these data to identify factors associated with a composite outcome of progression in Montreal behavior, hospitalization, and resection.

Results: An increased level of fecal calprotectin at the index visit was associated with subsequent progression of CD, independent of symptoms or disease location. The median level of fecal calprotectin at the index visit was 432 μg/g (IQR, 1365-998 μg/g) in patients who reached the composite end point vs 180 μg/g (IQR, 50-665 μg/g) in patients who did not. In multivariable analysis, a cut-off value of 115 μg/g calprotectin identified patients who met the end point with a hazard ratio of 2.4 (95% CI, 1.8-3.1; P < .0001).

Conclusions: In a retrospective analysis of patients with CD, we found that measurements of fecal calprotectin made during routine monitoring can identify patients at risk for disease progression, independent of symptoms or disease location. It is therefore important to screen asymptomatic patients for mucosal inflammation and pursue complete resolution of inflammation.