Development of the Irritable Bowel Syndrome Cognitive Affective Scale: a brief self-report measure for clinical and research settings.

OBJECTIVES

Measures of cognitive-affective processes believed to underlie Irritable Bowel Syndrome (IBS) symptom expression are used widely in both clinical and research settings. When combined, these measures can be time-consuming and it is not clear whether they evaluate distinct or overlapping constructs. With this study, we seek to identify the most critical cognitive-affective components contributing toward the expression of IBS and to identify which items in these constructs might be streamlined into a single, brief self-report measure.

PATIENTS AND METHODS

This measure was developed according to Food and Drug Administration guidelines for patient-reported outcome development. First, authors consolidated existing cognitive-affective measures (visceral sensitivity, anxiety sensitivity, and pain catastrophization) into a single questionnaire. Second, a principal components factor analysis was carried out on the basis of responses from a sample of participants with IBS. Third, on the basis of the results of the factor analysis, items were reduced to the final brief self-report measure and preliminary validity/reliability analyses (Cronbach's α, correlation with other related constructs) were carried out.

RESULTS

An initial, 44-item measure was created. In all, 179 patients with ROME-III IBS completed an online survey. Principal component analysis and item reduction yielded a 15-item scale with three factors: pain catastrophization, visceral hypervigilance, and extraintestinal hypervigilance. The final three factors showed comparable internal consistencies (α>0.90), concurrent validity, and predictive validity compared with the original 44 items.

CONCLUSION

Although more research is warranted, the 15 items identified appear to provide an accurate measure of two important cognitive-affective constructs in the IBS population.