Type, rather than number, of mental and physical comorbidities increases the severity of symptoms in patients with irritable bowel syndrome

Clin Gastroenterol Hepatol. 2013 Sep;11(9):1147-57. doi: 10.1016/j.cgh.2013.03.011. Epub 2013 Mar 21.


Background & aims: Irritable bowel syndrome (IBS) has significant mental and physical comorbidities. However, little is known about the day-to-day burden these comorbidities place on quality of life (QOL), physical and mental function, distress, and symptoms of patients.

Methods: We collected cross-sectional data from 175 patients with IBS, which was diagnosed on the basis of Rome III criteria (median age, 41 years; 78% women), who were referred to 2 specialty care clinics. Patients completed psychiatric interviews, a physical comorbidity checklist, the IBS Symptom Severity Scale, the IBS-QOL instrument, the Brief Symptom Inventory, the abdominal pain intensity scale, and the Short Form-12 Health Survey.

Results: Patients with IBS reported an average of 5 comorbidities (1 mental, 4 physical). Subjects with more comorbidities reported worse QOL after adjusting for confounding variables. Multiple linear regression analyses indicated that comorbidity type was more consistently and strongly associated with illness burden indicators than disease counts. Of 10,296 possible physical-mental comorbidity pairs, 6 of the 10 most frequent dyads involved specific conditions (generalized anxiety, depression, back pain, agoraphobia, tension headache, and insomnia). These combinations were consistently associated with greater illness and symptom burdens (QOL, mental and physical function, distress, more severe symptoms of IBS, and pain).

Conclusions: Comorbidities are common among patients with IBS. They are associated with distress and reduced QOL. Specific comorbidities are associated with more severe symptoms of IBS.

Keywords: 12-item Short Form; BSI; Brief Symptom Inventory; Chronic Disease; Comorbidity; DSM; Diagnostic and Statistical Manual of Mental Disorders; GAD; GERD; GI; GSI; HRQOL; Health-Related Quality of Life; IBS; IBS-SSS; IBSOS; Irritable Bowel Syndrome Outcome Study; Irritable Bowel Syndrome Symptom Severity Scale; LBP; MCS; MDD; MINI; MINI International Neuropsychiatric Interview; Mental Functioning; NIH; National Institutes of Health; PCS; QOL; SF-12; SF-12 Mental Component Score; SF-12 Physical Component Score; Stress; Transdiagnostic; gastroesophageal reflux disease; gastrointestinal; generalized anxiety disorder; global severity index; health-related quality of life; irritable bowel syndrome; low back pain; major depression disorder; quality of life.

MeSH terms

  • Abdominal Pain / complications
  • Adolescent
  • Adult
  • Aged
  • Comorbidity
  • Cross-Sectional Studies
  • Female
  • Humans
  • Irritable Bowel Syndrome / pathology*
  • Irritable Bowel Syndrome / psychology*
  • Male
  • Mental Disorders / complications
  • Middle Aged
  • Quality of Life
  • Severity of Illness Index*
  • Young Adult