Validation of a self-reported work disability questionnaire for ulcerative colitis

© 2018 the Author(s). Published by Wolters Kluwer Health, Inc. This is an open access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal. Ulcerative colitis (UC) may severely limit patients' capacity to work. Recently, we validated a work disability questionnaire (WDQ) for Crohn disease. As UC shares clinical characteristics with Crohn disease, we hypothesized that the questionnaire might also be useful for UC. The study was aimed to validate the WDQ for use in UC. Consecutive patients with UC (n = 142, 67 women; age 48 ± 1) completed the UC-WDQ and the inflammatory bowel disease questionnaire-9 (IBDQ-9), and EuroQoL-5D quality-of-life questionnaires. Validation of the UC-WDQ included an assessment of its construct validity, including: discriminant validity, convergent validity, and reproducibility (test-retest). We also calculated the intraclass correlation and the Cronbach alpha. 1. Discriminant validity: Mean UC-WDQ scores were 12.8 ± 4.4 (remission phase) and 17.2 ± 6.1 (with clinical activity) (P < .05). 2. Convergent validity: The correlations of UC-WDQ were r = 0.74 (P < .001) with IBDQ, r = 0.44 (P < .01) with disease activity, r = 0.56 (P < .01) with EuroQoL-5D, and r = 0.60 (P < .01) with the EuroQoL-5D visual scale. 3. Reproducibility: Test-retest reproducibility: UC-WDQ scores obtained after a 2-week interval were similar (15.8 vs 15.1), (r = 0.91, P < .01). Intraclass correlation was 0.93 (95% confidence interval 0.92-0.95). Cronbach alpha was 0.94. The UC-WDQ is a valid and reliable tool for measuring work disability in patients with UC.