Identifying Symptoms of Irritable Bowel Syndrome in Patients with Inflammatory Bowel Disease

Patients who have inflammatory bowel disease (IBD), even those who are in clinical remission, often exhibit symptoms consistent with irritable bowel syndrome (IBS). The presence of IBS symptoms can complicate the assessment and management of IBD, as IBS symptoms can appear to mimic the symptoms of active IBD, leading clinicians to unnecessarily employ invasive endoscopic or radiological procedures and initiate anti-inflammatory and/or immunomodulatory therapy. To prevent this, it is important to learn more about the potential causes of IBS-type symptoms in patients with IBD and the impact these symptoms can have on assessment and management of IBD.

To examine these issues, the authors of “Symptoms of Irritable Bowel Syndrome in Patients with Inflammatory Bowel Disease: Examining the Role of Sub-clinical Inflammation and the Impact on Clinical Assessment of Disease Activity,” published in Alimentary Pharmacology and Therapeutics, recruited a cohort of 169 patients with a verified diagnosis of IBD and assessed them for IBD disease activity/severity, presence of intestinal inflammation, and IBS symptoms.

Patients completed the simple clinical colitis activity index (SCCAI) for ulcerative colitis, the Harvey-Bradshaw index (HBI) for Crohn’s disease, and the irritable bowel section of the Rome III diagnostic questionnaire for adult functional disorders. Patients were also assessed for mood disorders using the Hospital Anxiety and Depression Scale.

Based on results from these screening instruments and patients’ C-reactive protein (CRP) levels, investigators defined clinical remission in ulcerative colitis as SCCAI <3 points and CRP <10 mg/L, and clinical remission in Crohn’s disease as HBI <5 points and CRP <10 mg/L. Patients were classified as having “clinically active” disease if they had SCCAI ≥3 points or HBI ≥5 points. Patients with SCCAI <3 or HBI <5, but a CRP >10 mg/L, were defined as “unclassified.”

Investigators also took stool samples from 109 patients to measure fecal calprotectin levels, with levels of < 90 μg/g indicating biochemical remission of IBD.

The mean age of the cohort was 44 years, with women making up 64% of the group. There were 101 cases of ulcerative colitis and 68 of Crohn’s disease.

Results

Overall, 97 patients were in remission, 54 had active disease, and 18 were unclassified. Prevalence of IBS symptoms in patients in remission was 32%. The authors reported that among patients in remission, IBS symptoms “were significantly more common in female patients and were associated with higher levels of anxiety and depression.”

There was no statistical difference between fecal calprotectin levels of patients in clinical remission with IBS symptoms compared with those without IBS symptoms. However, fecal calprotectin levels were “significantly higher” in the clinically active group.

In patients with ulcerative colitis who were in remission, median fecal calprotectin levels were higher (71 μg/g) in patients with IBS symptoms than in those without (35 μg/g). Scores were similar for patients with Crohn’s disease in remission (111 μg/g in patients with IBS symptoms vs. 50 μg/g in those without).

Forty-eight (44%) of the 109 patients who provided a stool sample had fecal calprotectin levels indicating clinical remission. IBS symptom prevalence in this group was 31%.

In their discussion of these results, the authors wrote that this study “demonstrates that IBS-type symptoms are significantly more common in female IBD patients, are associated with high anxiety levels, and can occur in patients with no active inflammation. Together, these features are similar to those exhibited by ‘true’ IBS occurring in the general population, and suggest that in some IBD patients the same condition may be responsible for producing their symptoms

These results show “that IBD patients with IBS-type symptoms share similar characteristics to people diagnosed with IBS in the general community, thereby suggesting that these conditions are not mutually exclusive and may be coexisting in a considerable number of IBD patients.” With this study highlighting “the substantial number of patients who experience IBS-type symptoms, despite having normal calprotectin levels,” clinicians are advised that “healing inflammation is not necessarily the end point in therapy, and that further management of symptoms may be required.”

Finally, accurately identifying IBS symptoms in patients with IBD may enable clinicians to more effectively target IBS-appropriate interventions in this population, as the effectiveness of these strategies in unselected IBD patients is quite limited. The authors concluded that additional clinical trials are needed “to determine whether those therapies that are effective in treating IBS are also useful in the management of IBS-type symptoms in IBD patients.”