Introduction C-reactive protein (CRP) is an established marker of disease activity in inflammatory bowel disease (IBD). However not all flares in IBD are associated with an elevated CRP. This raises the possibility that some patients are not CRP producers1,2,3. In this retrospective observational study, we have assessed if patients consistently produce a low or high CRP level in response to a flare in IBD.
Methods 31 patients were identified, over a 5 year period across 3 centres, with endoscopic mucosal assessments of two consecutive exacerbations of IBD which were at least 3 months apart. Patients were included if they had a CRP measurement within 7 days of each endoscopic examination (colonoscopy or flexible-sigmoidoscopy), and if they had active inflammatory colitis confirmed on mucosal biopsy. A CRP non-producer was defined as a CRP level of less than 10mg/L as according to the laboratory reference range used in the centres.
Results In the cohort of 31 patients, 19 had biopsy proven UC, 3 had Crohn’s disease, 6 were unclassified, and 3 had differing classifications of Crohn’s disease and UC on successive endoscopies. There was an overall mean period of 11.3 months between successive endoscopies. 17 patients were CRP non-producers and 9 were CRP producers during successive IBD flares. The table below shows the disease classification in different CRP response groups.
Disease extent was defined in both flares in 97% of patients. In the CRP non-producer group, 10 out of 17 (59%) patients had left sided disease or proctitis compared to 4 out of 8 (50%) in the CRP producer group. This difference in proportion did not reach statistical significance as assessed by Fisher’s exact test. Three of the five patients with a variable CRP response had more extensive disease at the time of the higher CRP level.
Conclusion Most patients (84%) in this study had a consistent CRP response; but this was not universal. Disease extent appears to contribute to CRP, but patient specific factors also appear to play a role.
Disclosure of Interest None Declared.
Gut. 2008 Nov; 57(11):1518–23. Epub 2008 Jun 19. C-reactive protein: a predictive factor and marker of inflammation in inflammatory bowel disease. Results from a prospective population-based study. Henriksen M, et al. IBSEN Study Group
Inflamm Bowel Dis. 2005 Aug; 11(8):707–12..Correlation of C-reactive protein with clinical, endoscopic, histologic, and radiographic activity in inflammatory bowel disease. Solem CA, et al.
Inflamm Bowel Dis. 2004 Sep; 10(5):661–5.C-reactive protein as a marker for inflammatory bowel disease. Vermeire S, et al.