Fecal calprotectin and its correlation with inflammatory markers and endoscopy in patients from India with inflammatory bowel disease

Abstract

Introduction: In clinical practice, endoscopic findings are often used for assessing disease activity in inflammatory bowel disease (IBD). In recent years, blood and stool markers are being increasingly used for this purpose. Among them, the fecal calprotectin (FC) level is probably the most favored. Data on the reliability of FC are lacking from countries like India, where gut infections are common.

Objective: The aims of this study were to compare the FC level with the erythrocyte sedimentation rate (ESR) and the C-reactive protein (CRP) as non-invasive markers of IBD and, in patients with ulcerative colitis (UC), and to study its correlation with disease extent, clinical activity, and endoscopic severity.

Methods: Records of patients with IBD who had tests for FC, ESR and CRP and colonoscopy done within a 2-week period, between 2012 and 2014, were retrieved. Sixty-three patients (UC 32, Crohn's disease [CD] 31) were included for analysis. ESR, CRP and FC were compared to endoscopy to assess inflammation.

Results: Patients with UC had higher levels of FC than those with ileocolonic CD (median FC 800 mcg/g vs. 619 mcg/g, respectively; p = 0.04). FC levels correlated with CRP (r = 0.4, p < 0.001) but not with ESR (r = 0.21, p = 0.09). In patients with UC with endoscopic evidence of inflammation, more (86.9 %) had FC > 200 mcg/g (cut-off for disease activity in our laboratory) than had ESR >20 mm in the first hour (60.6 %) or positive CRP (65.6 %) (< 0.01); FC levels increased with increasing endoscopic Mayo score (p = 0.001) and Truelove-Witt's clinical severity score (p = 0.006), but did not correlate with disease extent (p = 0.7). The best FC cut-off level to identify 'active UC' (Mayo grade 2 or more) was 800 mcg/g.

Conclusion: Fecal calprotectin level correlates with CRP but not with ESR. In patients with UC with inflammation, FC > 200 mcg/g is more often positive than raised ESR or CRP; it also correlates with clinical and endoscopic activity but not with disease extent. FC level > 800 mcg/g can be used to differentiate active from inactive UC.

Keywords: C-reactive protein; Fecal calprotectin; Inflammatory markers.