title: Predictors of patient-assessed illness severity in irritable bowel syndrome.
abstract: BACKGROUND
  Conceptual models suggest that "irritable bowel syndrome (IBS) severity" is a multidimensional outcome that is related to, yet distinct from, health-related quality of life (HRQOL). Existing severity questionnaires are largely based on physician rather than patient-based ratings. Since severity is a patient-centered outcome, it is essential that future instruments are based on patients' self-perceptions of severity. We measured patient-derived predictors of severity in a large cohort of IBS patients.
  
  
  METHODS
  We performed a cross-sectional analysis in 755 IBS patients recruited at a university-based center. Subjects completed a bowel symptom questionnaire, SCL-90, and SF-36. The main outcome was patient-assessed "overall severity of gastrointestinal symptoms," as measured on a 0-20 scale (20 = most severe). We first developed a conceptual model of IBS, and then performed bivariate analyses to identify biopsychosocial predictors of severity. We then entered significant predictors into a multivariable model to measure the independent association of each predictor with severity.
  
  
  RESULTS
  Six factors predicted severity: (a) abdominal pain rating (P < 0.001); (b) belief that "something serious is wrong with body" (P < 0.001); (c) straining with defecation (P= 0.001); (d) myalgias (P= 0.02); (e) urgency with defecation (P= 0.03); and (f) bloating (P= 0.05). Severity correlated highly with HRQOL in bivariate, but not multivariate, analysis.
  
  
  CONCLUSIONS
  Patient-derived severity in IBS is related to, yet distinct from, generic HRQOL. IBS severity is predicted by abdominal pain, bloating, straining, urgency, myalgias, and disease-related concern. These symptoms fall along both poles of the "brain-gut axis," indicating that a full assessment of patient severity must include a balanced biopsychosocial history.
authors.affiliation: VA Greater Los Angeles Healthcare System, Center for Outcomes Research and Education, Los Angeles, California, USA.
authors.forename: Brennan
authors.initials: B
authors.lastname: Spiegel
authors.forename: Amy
authors.initials: A
authors.lastname: Strickland
authors.forename: Bruce D
authors.initials: BD
authors.lastname: Naliboff
authors.forename: Emeran A
authors.initials: EA
authors.lastname: Mayer
authors.forename: Lin
authors.initials: L
authors.lastname: Chang
mesh_terms: D015746:Abdominal Pain / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D015994:Incidence; D043183:Irritable Bowel Syndrome / Q000150:complications* / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D011379:Prognosis; D011788:Quality of Life; D012189:Retrospective Studies; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires