Development and validation of a 13-item short version of the inflammatory bowel disease self-efficacy scale.

ABSTRACT

BACKGROUND: The inflammatory bowel disease self-efficacy scale (IBD-SES) is an instrument used across many countries to measure important health outcomes of patients with inflammatory bowel disease (IBD). We aimed to develop and validate a substantially shorter version of this scale to reduce patients' response burden. METHODS: A total of 919 patients with IBD, 482 recruited from an IBD clinic and 437 recruited online, completed the Japanese version of the original, 29-item IBD-SES. These data were then used to develop a shorter version of the scale. The original 29 items of the IBD-SES were reduced with three analytic steps: assessing ceiling and floor effect, testing correlation between items, and assessing test-retest reliability. The resulting 13-item IBD-SES was evaluated for construct validity by confirmatory factor analysis, criterion validity by Pearson correlation coefficients with original version, and internal consistency by item-total correlations and the Cronbach's α coefficient. RESULTS: The short version consisted of the same four subscales "managing stress and emotions," "managing medical care," "managing symptoms and disease," and "maintaining remission" as the original scale. The fit indices of the final model were as follows normed chi-square, 7.18 (p < 0.001); comparative fit index, 0.94; goodness-of-fit index, 0.93; adjusted goodness-of-fit index, 0.89; parsimony goodness-of-fit index, 0.60; and root mean square error of approximation, 0.084. Correlation of each subscale with the original scale was high (0.97-0.98). Cronbach's α for each subscale ranged from 0.68 to 0.86. CONCLUSIONS: A short version of the IBD-SES was developed. The results confirmed the improved validity, reliability, and psychometric properties of the IBD-SES. TRIAL REGISTRATION Not applicable.