Fecal Calprotectin in Assessing Endoscopic and Histological Remission in Patients with Ulcerative Colitis

Persistent active endoscopic and histological inflammation is associated with poorer outcomes in ulcerative colitis (UC). Fecal calprotectin is a surrogate marker of endoscopic and histological remission.

To confirm the correlation between fecal calprotectin and endoscopic or histological disease activity and to define the optimal cutoff value to detect endoscopic and histological remission.

From a prospectively maintained database, we analyzed 61 UC patients who had fecal calprotectin measurement and endoscopy performed within 1 month. Endoscopic activity was graded using the Mayo endoscopic subscore (MES). Histological remission was defined as normal histology or quiescent histological activity.

Eighteen patients (29.5%) and five patients (8.1%) had endoscopic remission defined as MES ≤ 1 or MES = 0, respectively. We observed a significantly lower median level of fecal calprotectin in patients with endoscopic remission than those with endoscopic activity for both definition of endoscopic remission, i.e., MES ≤ 1 (158 vs 490 µg/g, p = 0.0005) or MES = 0 (94 vs 414 µg/g, p = 0.013). Seven patients (11.5%) were in histological remission. They had a lower median level of fecal calprotectin than those with active histological inflammation (107 vs 416 µg/g, p = 0.016). Using a ROC curve, fecal calprotectin < 250 µg/g predicted endoscopic remission (MES ≤ 1) with a sensitivity of 67% and specificity of 77%, while fecal calprotectin < 200 µg/g predicted histological remission with a sensitivity of 71% and specificity of 76%.

Fecal calprotectin level correlated with both endoscopic activity and histological activity and is a reliable biomarker in assessing mucosal healing in UC.