Abstract
Background
Crohn’s disease (CD) is a type of inflammatory bowel disease (IBD) that causes inflammation of the gastrointestinal tract. C-reactive protein (CRP) is an inflammatory biomarker measured in the serum that is typically elevated during periods of disease activity and assists with guiding therapy. Previous studies have shown that 20–25% of CD patients do not produce CRP during IBD flares, due to genetic polymorphisms in the CRP-producing gene. It was hypothesized that this subset of patients will be on a different treatment regimen than CD patients that do produce CRP.
Aims
We conducted this case-control study to evaluate the treatment differences in CRP-non-producing CD patients as compared with CRP-producing CD patients.
Methods
Charts of outpatients seen in a GI clinic in Saskatoon over a two-year period were evaluated. Patients were assigned to two arms: CRP-producers and CRP-nonproducers. CRP-nonproducers were defined as patients with a maximum CRP level less than 10.5 mg/L with objective evidence of inflammation during a flare of CD, such as inflammation on endoscopy, imaging, or an elevated fecal calprotectin. A total of 265 CD patients were included, with 57 CRP-nonproducers (21.5%), and a mean follow-up time of 2.9 years. The primary end point was the class of IBD medication taken at the start and conclusion of the study. Secondary end points included duration and location of disease, age at diagnosis, requirement of surgical therapy for CD, follow-up time, number of visits to the IBD clinic, number of IBD-related hospitalizations, ferritin, hemoglobin, B12, and albumin levels. Results were analyzed with Fischer’s exact test and the Z-test.
Results
From the 265 CD patients reviewed, a total of 57 CRP-non-producers (21.5%) were identified. Compared to CRP-producers, CRP-nonproducers were less likely to be on biologic therapy at the start of the study (23% vs 35%, p=0.044; odds ratio 0.66) and at the conclusion of the study (47% vs 65%, p=0.007; odds ratio 0.72). CRP-nonproducers were much more likely to be on no therapy or 5-aminosalicylates at the start of the study (68% vs 43%, p=0.0006; odds ratio 1.58) and at the end of the study (44% vs 25%, p=0.005; odds ratio 1.76).
Conclusions
Lack of a CRP response in Crohn’s disease was associated with lower rates of biologic therapy.
Funding Agencies
None