Solem CA et al. (2005) Correlation of C-reactive protein with clinical, endoscopic, histologic, and radiographic activity in inflammatory bowel disease. Inflamm Bowel Dis 11: 707–712

A retrospective study at the Mayo Clinic has examined the relationship between serum C-reactive protein (CRP) concentrations and other measures of disease activity in patients with inflammatory bowel disease (IBD).

Patients with Crohn's disease (CD; n = 104) or ulcerative or indeterminate colitis (UC/IC; n = 43) who had undergone a CRP test, colonoscopy and either a small-bowel follow-through or CT enterography, all performed within a 14-day period, were identified. Medical test results were analyzed, including laboratory biomarkers of inflammation, small-bowel radiographic imaging, colonoscopy and biopsy pathology. Clinical activity was defined using adapted American College of Gastroenterology practice guidelines.

In CD patients, an increased concentration of CRP, defined as >0.8 mg/dl, was significantly associated with moderate–severe clinical activity, and showed a significant correlation with clinical disease activity in UC/IC patients. Elevated levels of CRP showed a significant correlation with several biomarkers of inflammation (anemia, hypoalbuminemia and elevated erythrocyte sedimentation rate), and with active disease at colonoscopy, in all IBD types. Abnormal small-bowel radiographic imaging was not significantly associated with increased CRP levels, but the authors state that this might be because of the different sensitivities of the methods used.

The authors conclude that the CRP concentration in IBD patients correlates with a number of factors, including other inflammatory biomarkers and clinical disease activity, but that larger studies are needed to explore further the use of CRP levels in predicting IBD disease activity.