Résumé
Background: Serum procalcitonin level (SPL) may reflect non-infectious inflammation. Aim: To assess the correlation of SPL with clinical, biological, endoscopic and radiological markers of disease activity in inflammatory bowel diseases (IBD) and to evaluate the additional diagnostic benefit of measuring SPL to that of C-reactive protein (CRP) for disease activity appraisal. Methods: We performed a prospective observational study. Spearman's rank correlation and receiver operating characteristic analysis were used to evaluate correlation and diagnostic accuracy, respectively. Results: In Crohn's disease (CD) (n=30), SPL was strongly correlated with clinical, biological, endoscopic and radiological disease activity markers. In CD, a SPL >0.14 µg/L demonstrated a high accuracy for detecting severe disease (Sensitivity=100%; Specificity=96%; AUROC=0.963; P=0.0001). The diagnostic accuracy of the 'SPL-CRP strategy' (CRP >5 mg/L and SPL >0.05 µg/L) was significantly superior to that of CRP alone for diagnosing severe CD (AUROC=0.783 versus 0.674; P=0.01). In ulcerative colitis (UC) (n=27), SPL was correlated with CRP and with endoscopic and radiological disease activity markers. Conclusions: In CD, the SPL was correlated with all disease activity markers and a cut-off of 0.14 µg/L could distinguish severe forms of the disease. The 'SPL-CRP strategy' was superior to CRP alone for diagnosing active or severe CD.