Clinical Predictors of Elevated C-Reactive Protein (CRP) among Patients with Active Inflammatory Bowel Disease: 975

Purpose: CRP is a useful inflammatory marker frequently used in the management of inflammatory bowel disease (IBD) pts. However, certain groups of pts have either normal or slightly elevated CRP despite significantly active disease. Our aim was to identify determinants of CRP levels in IBD pts. Methods: Pts with confirmed IBD and at least 2 of the following indicators of active disease (radiologic, endoscopic, pathologic or clinical) were included in the study. CRP level at the time of disease activity was measured. Demographics and disease characteristics including location, modifiers and phenotype were assessed. Non-parametric tests were used to assess associations and multivariate analysis was performed to find independent predictors. Results: 92 pts (64 with CD and 28 with UC), mean age 36 yrs (14–68) and mean age at diagnosis 27 yrs (9–62) were included in the study. Mean CRP level in the cohort was 3.9 mg/dl (0.3–21.4) and 14 pts had levels >10. CD and UC pts had comparable mean CRP level (3.2 vs 5.5; P= ns) Univariate analysis showed that among CD pts, colonic involvement was associated with higher CRP level compared to ileal disease only (1.7 vs 3.8; P= 0.01) and active perianal disease compared to no perianal involvement (1.4 vs 4.9; P= 0.005). Stricturing phenotype was associated with lower mean CRP (1.1) compared to fistulizing (5.3) and inflammatory (3.7) phenotypes (P= 0.02). Among UC pts, pancolitis was associated with higher CRP level compared to pts with lt sided or proctitis (5.1 vs 2.7; P= 0.02). In the entire group, older age at diagnosis was associated with higher CRP (P= 0.02). Neither smoking nor family history were associated with CRP level. All associations remained significant in the multivariate analysis. Conclusion: Colonic and perianal involvement in CD pts is associated with high CRP levels while stricturing phenotype and ileal disease are associated with lower levels. Among UC pts, pancolitis is associated with higher CRP levels. In IBD pts, in general, older age at diagnosis is associated with higher CRP levels. These characteristics may help to identify a group of patients in whom CRP can be used reliably to assess activity and follow response to treatment.