Histologic healing is emerging as a new therapeutic goal in both routine practice and clinical trials in ulcerative colitis (UC). However, it requires repeated endoscopies and biopsies. Faecal calprotectin is a non-invasive marker of mucosal healing (endoscopic and histologic healing).
To conduct a systematic review to clarify the correlation between faecal calprotectin levels and histologic activity in UC patients.
We searched PubMed/MEDLINE, EMBASE and Web of Science through September 2019 to identify studies in patients with confirmed diagnosis of UC, reporting the correlation between faecal calprotectin levels and histologic analysis.
Twelve studies enrolling 1168 patients were included in the final review. Histologic remission was defined according to nonvalidated scores in five articles and using partially validated scores in seven articles. Faecal calprotectin values were measured in 6 of 12 studies (50%) with the same kit, while the remaining six studies adopted individually different kits. A clear correlation between faecal calprotectin levels and histology was showed in all included studies. Eleven different faecal calprotectin cut-off points were identified to distinguish histological remission from histological activity, ranging from 40.5 to 250 μg/g.
Faecal calprotectin can be used to predict histologic remission in patients with UC, but the cut-off level varies across studies, according to the test used to measure this biomarker and according to the definition of histologic remission. Larger prospective studies using validated histologic indexes are needed to identify a globally accepted faecal calprotectin cut-off level to discriminate between histologic remission and histologically active disease.

© 2020 John Wiley & Sons Ltd.