Longitudinal Patterns of CRP Elevation and Crohnʼs Disease Severity

Abstract

Purpose: C-reactive protein (CRP) is a biochemical marker that correlates with inflammation in Crohn's disease (CD). CRP confirms active inflammation and may function as a prognostic indicator of poor outcome. CD currently lacks a severity index, which stratifies groups of patients based on their burden of illness over time. We hypothesized that patterns of CRP elevation in CD patients followed longitudinally may correlate with disease-related complications and function as a biochemical marker of severity. Methods: Prospectively recruited CD patients from a longitudinal IBD natural history registry followed between 2009 and 2011, with annual visits and CRP evaluation, were analyzed. Short IBD questionnaire (SIBDQ) and Harvey-Bradshaw Index (HBI) scores completed at each visit, patterns of IBD-related hospitalization, and emergency department (ED) use were analyzed. Mean SIBDQ scores over 3 years > 50 were considered good quality of life. Results: A total of 153 CD patients were included in our study; 42.5% (65) were males, while 57.5% (88) were females. Patients had a mean age of 43.4 years (SD 14.2; range 21.4-81.2 years). Sixty-five of the 153 patients (42.5%) had no CRP elevation during the study period, while 57.5% of patients (88) had at least one CRP elevation. Among the patients with elevation in CRP, 23.55% (36) had CRP elevation in 1 year, 20.3% of patients (31) had CRP elevation in 2 of the 3 years, while 13.7% (21) had CRP elevation in all 3 years of the study. When comparing ED visits, 54% of patients with at least one CRP elevation over 3 years had an ED visit, as compared to 30% of patients with normal CRP over 3 years (p=0.026). 67.2% of patients (43) with normal CRP elevation over 3 years had a good quality of life, which was significantly higher than CD patients with CRP elevations over 1, 2, and 3 years (41.7%, 33.3%, and 30%, respectively); p=0.002. When comparing hospitalizations, 64% of patients with at least one CRP elevation in any of the 3 years of the study period required a CD-related hospitalization, as compared to 20% of patients with no CRP elevation in these 3 years (p<0.001). The HBI was significantly higher in patients with any CRP elevation compared to no CRP elevation (3.4 vs. 5.3, p<0.001). Conclusion: Prospective evaluation of CRP elevation in CD patients over a 3-year study period correlated with increased rates of ED use and hospitalization. Persistent elevation in CRP over multiple years correlated with worse quality of life in CD. CRP elevation carries important prognostic ramifications for CD-related complications, and persistent CRP elevation may define a sub-group of CD patients with severe and refractory disease.