Comparison of changes in biomarkers with changes in endoscopic scores in patients with ulcerative colitis: a single-center, retrospective, observational study

Background Fecal occult blood concentration, fecal calprotectin (FC) level, serum C-reactive protein (CRP) level, and erythrocyte sedimentation rate (ESR) are valuable biomarkers for ulcerative colitis (UC); however, their clinical utility for longitudinal disease assessment requires further clarification. This retrospective, observational study aimed to assess the correlations among changes in the values of these biomarkers and endoscopic activity scores in patients with UC. Methods We examined the relationship between longitudinal variations in endoscopic activity scores, including the Mayo endoscopic subscore (MES), ulcerative colitis endoscopic index of severity (UCEIS), and sum of Mayo endoscopic subscores (S-MES), and corresponding changes in biomarker values within the same cohort of patients with UC using Spearman's rank correlation coefficient analysis. Results All endoscopic scores and biomarkers were significantly correlated with disease activity, with corresponding increases or decreases (P < 0.05). Changes in the MES had the strongest correlation with changes in FC level (r = 0.62). The changes in the UCEIS had the strongest correlation with changes in fecal occult blood concentration (r = 0.67). Changes in S-MES had the strongest correlation with changes in FC level (r = 0.66). Changes in fecal occult blood concentration and FC level were strongly correlated (r = 0.55), as were changes in serum CRP level and ESR (r = 0.58). Conclusions All four biomarkers reflected endoscopic activity in UC; however, changes in fecal occult blood concentration and FC level had stronger correlations with changes in endoscopic scores than changes in blood biomarker values. FC level assessment is valuable for monitoring inflammatory activity during remission maintenance, whereas fecal occult blood concentration accurately reflects mucosal bleeding. Serum CRP level and ESR are useful adjunctive biomarkers, particularly in cases of increased disease activity.