Understanding Gastrointestinal Symptoms in Patients With Concomitant Irritable Bowel Syndrome and Inflammatory Bowel Disease: A Cross-Sectional Study From IBD Partners

Background: Inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) are gastrointestinal (GI) disorders often characterized by bowel irregularity and abdominal pain. Unlike IBS, IBD is identified by the presence of bowel inflammation. If IBD patients continue to have symptoms when their inflammation is well controlled, they can be concurrently diagnosed with IBS. Our objective was to describe detailed differences in GI symptoms, using the GI PROMIS inventory, in IBD-IBS patients and IBD-only patients. We also sought to identify demographic differences between these groups. Methods: We conducted a cross-sectional study within IBD Partners Internet-based cohort of individuals living with Crohn’s disease (CD) and ulcerative colitis (UC). Participants completed surveys including clinical and demographic information, disease activity instruments including short Crohn’s disease activity index (sCDAI) and simple clinical colitis activity index (SCCAI), whether they had been diagnosed by a provider with IBD-IBS, as well as the GI PROMIS inventory of symptoms. The GI PROMIS inventory includes 8 symptom domains: gastroesophageal reflux (GER), disrupted swallowing, diarrhea, nausea/vomiting, belly pain, gas/bloat, incontinence, and constipation. Standardized T scores were calculated with 50 as the general population reference. Percentiles for each category of symptoms were also calculated. Bivariate analyses via t-test or chi-square test were utilized to compare IBD-IBS to IBD only populations using both T scores or percentile groups. All analyses were stratified by CD vs. UC. Results: The study included 270 IBD-IBS patients and 489 IBD-only patients, 495 patients with CD and 264 with UC. A total of 41% of IBS patients and 45% of IBD-only patients met criteria for remission of their IBD. Overall, the IBD-IBS patients were older (45.2 vs. 41.8, p=0.001), and had a higher body mass index (26.5 vs. 25.4, p=0.025). IBD-IBS patients were more likely to report use of serotonin and norepinephrine reuptake inhibitors (8% vs. 4%, p=0.044), tricyclic antidepressants (TCAs) (5% vs. 0%, P< 0.001), and benzodiazepines (20% vs. 10%, P< 0.001). There was no statistically significant difference in the use of IBD-specific therapies. The most prevalent symptoms in the IBD-IBS and IBD-only populations were comparable among the groups: gas/bloat (81% vs. 77%, p=0.140), belly pain (72% vs. 66%, p=0.063), and diarrhea (73% vs. 66%, p=0.064). The IBD-IBS group had significantly worse T scores for GER (40.7 vs. 37.5, p=0.001), disrupted swallowing (43.5 vs. 41.9, p=0.001), nausea and vomiting (49.1 vs. 46.4, P< 0.001), and belly pain (51.3 vs. 48.7, p=0.013). After stratification, CD patients had similar differences in symptom profiles as the overall population, however there were no significant differences in symptoms for UC patients with IBD-IBS vs. IBD only. Conclusions: Although classic definitions of IBS include a change in bowel habits with abdominal pain, patients with IBD-IBS have other increased symptom profiles. A full assessment of GI symptoms is therefore warranted. These symptom differences are more profound in CD as compared to UC patients. We also found a low rate of neuromodulator use among IBD-IBS patients (only 5% using TCAs). This likely represents a missed opportunity for awareness and treatment of IBS in IBD patients.