Combined evaluation of fecal calprotectin and C-reactive protein as a therapeutic target in the management of patients with Crohn's disease

Objectives: Proper management of the inflammatory process in Crohn's disease (CD) results in lower rates of complications. The objective of this study was to investigate the performance of isolated and combined use of fecal calprotectin (FC) and serum levels of C-reactive protein (CRP) as markers of inflammatory activity in CD and the possibility of their use as a therapeutic target.

Patients and methods: Patients with CD and indication for colonoscopy were prospectively enrolled in the study and allocated according to the presence or absence of endoscopic inflammatory activity. The correlation between FC and CRP levels and the Simplified Endoscopic Score of Crohn's Disease (SES-CD) was performed, and the accuracy of these markers was evaluated for the diagnosis of inflammatory activity, when used alone or in series.

Results: Eighty colonoscopies were performed in patients with CD. The FC cut-off value of 155μg/g showed high sensitivity (96%) and accuracy (78%) for the diagnosis of endoscopic activity. For CRP, the value of 6.7mg/L demonstrated sensitivity of 75% and specificity of 67%. The sequential usage of these markers (FC+CRP) showed greater specificity (82%) when compared to the use of these markers alone. Depending on the probability of inflammatory activity, different scenarios were used to evaluate the performance of these markers and an algorithm is proposed.

Discussion: Combined analysis of FC and CRP, when performed consecutively, allows decisions to be made with a high degree of certainty and even eliminates the need for colonoscopy in many situations.