Validity, reliability, and responsiveness of the Brazilian version of the instrument World Health Organization Disability Assessment Schedule (WHODAS 2.0) for individuals with obstructive sleep apnoea

Abstract

BackgroundObstructive sleep apnoea (OSA) is a disabling health condition, and there is no disease-specific patient-reported outcome instrument to assess individuals with OSA. ObjectivesTo evaluate the psychometric properties of the Brazilian version of the World Health Organization Disability Assessment Schedule (WHODAS 2.0) in individuals with OSA. MethodsOne hundred individuals with OSA responded to the WHODAS 2.0 version of 36 items, the Epworth Sleepiness Scale (ESS), the Pittsburgh Sleep Quality Index (PSQI), and the 12-item health survey (SF-12). Internal consistency, convergent and discriminative validity, and responsiveness to continuous positive airway pressure (CPAP) were the psychometric properties tested. ResultsCronbach's α values indicate good internal consistency (0.91 – 0.73), except for the self-care domain (α = 0.52). Convergent validity indicated an excellent correlation (r = -0.80) between the domains of functioning and quality of life. Discriminative validity showed no association between OSA severity and functioning (p = 0.90). The responsiveness to CPAP treatment showed a large effect size (r = 0.82; p < 0.05) ConclusionsThe WHODAS 2.0 instrument is valid, reliable, and responsive for assessing individuals with OSA.