Association of Fecal Calprotectin Level and Combined Endoscopic and Radiologic Healing in Patients with Crohn's Disease Receiving Anti-Tumor Necrosis Factor Therapy.

BACKGROUND AND AIMS: Combined endoscopic and radiologic healing, or deep healing, is associated with favorable outcomes in patients with Crohn's disease; thus, noninvasive biomarker for predicting deep healing would be invaluable. We evaluated the usefulness of fecal calprotectin for predicting deep healing in patients with Crohn's disease receiving anti-tumor necrosis factor therapy. METHODS: We analyzed the records of patients with Crohn's disease who received anti-tumor necrosis factor therapy and underwent endoscopic evaluation, radiologic evaluation, and fecal calprotectin measurement within a period of three months between August 2017 and November 2018. Results of endoscopic and radiologic studies were independently reviewed by two gastrointestinal endoscopists and a gastrointestinal radiologist, respectively. Serum C-reactive protein and albumin were also measured. RESULTS: Out of 268 patients analyzed, 77 (28.7%) had deep healing, 36 (13.4%) had endoscopic healing only, 36 (13.4%) had radiologic healing only, and 119 (44.4%) had neither. The median duration of anti-TNF treatment was 40.0 months. The deep healing group had the lowest median fecal calprotectin level (56.5 mg/kg) among the four groups (p < 0.001). The fecal calprotectin cutoff level of 81.1 mg/kg showed a sensitivity of 0.623 and a specificity of 0.817 in predicting deep healing (area under the receiver operating characteristic curve [AUROC], 0.767; 95% confidence interval, 0.702-0.832). Adding serum C-reactive protein and serum albumin to fecal calprotectin further increased the AUROC to 0.805 (95% confidence interval, 0.752-0.858). CONCLUSION: Fecal calprotectin, when combined with serum C-reactive protein and albumin, showed acceptable performance in predicting deep healing in patients with Crohn's disease.