Two Specific Proteins Allow the Exclusion of IBD in Patients with Irritable Bowel Syndrome

Two Specific Proteins Allow the Exclusion of IBD in Patients with Irritable Bowel Syndrome

shutterstock_244122988A new study led by researchers at University of Michigan Health System recently analyzed the importance of several screening tests to exclude the diagnosis of inflammatory bowel disease (IBD) in patients with irritable bowel syndrome (IBS). The study was published in The American Journal of Gastroenterology and is entitled “A Meta-Analysis of the Utility of C-Reactive Protein, Erythrocyte Sedimentation Rate, Fecal Calprotectin, and Fecal Lactoferrin to Exclude Inflammatory Bowel Disease in Adults With IBS.

IBD corresponds to a chronic inflammatory condition of the digestive tract that primarily comprises ulcerative colitis and Crohn’s disease. It is characterized by vomiting, abdominal pain, rectal bleeding, diarrhea, internal cramps in the pelvis region, fatigue and weight loss. IBD can lead to life-threatening complications such as iron deficiency anemia.

IBS is a chronic disorder that affects the colon (large intestine) and is characterized by abdominal pain, cramping, swelling, gas, diarrhea and constipation. Different from IBD, IBS does not cause changes in bowel tissue.

“Though IBD is uncommon in patients with typical IBS symptoms and no alarming features, patients and providers remain concerned about this possibility,” said the study’s senior author Dr. William D. Chey in a news release.

Researchers performed a systematic review and a meta-analysis to determine the value of assessing the erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), fecal lactoferrin and fecal calprotectin for the discrimination between patients with IBD, IBS and healthy individuals. 1,252 studies were reviewed and from these 12 were selected for the meta-analysis comprising a total of 1,059 IBD patients, 595 IBS patients and 491 healthy controls.

The research team found that none of the biomarkers analyzed was able to discriminate IBS patients from healthy controls; on the other hand, calprotectin and CRP allowed to distinguish IBD patients from healthy controls and IBS patients. The likelihood of having IBD increased with calprotectin levels, where patients with less than 40 µg/g had a chance of 1% or less of having the disease. The likelihood of IBD also increases with higher CRP levels, where CRP levels equal or inferior to 0.5 mg/dL indicating a likelihood of having IBD of 1% or less, levels equal or higher than 1.7 mg/dL suggestive of a IBD probability higher than 52%, and levels higher than 2.7 mg/dL indicating an IBD probability of more than 90%.

“Serum CRP and fecal calprotectin provide a noninvasive means by which to exclude IBD in patients with IBS symptoms and no alarming features,” concluded Dr. Chey. A CRP level of ≤ 0.5 mg/dL or a calprotectin level ≤ 40 μg/g basically excludes IBD in patients with IBS symptoms.

“Based upon these results, it may be reasonable for clinicians to consider ordering CRP or fecal calprotectin to improve their confidence in making a diagnosis of IBS,” concluded the researchers. The team believes that “prospective studies to evaluate the clinical utility and cost effectiveness of adding CRP or fecal calprotectin to the evaluation of patients with suspected IBS in different populations would be of considerable interest.”