[Structure and metric properties of a questionnaire to measure disability in mobility activities in patients with chronic obstructive pulmonary disease (DIAMO-COPD questionnaire)]

Abstract

Objective: The aim of this study was to adapt a disability questionnaire in mobility activities (DIAMO-EPOC) incorporating scales based on the conceptual framework of the International Classification of Functioning, Disability and Health, and to examine its structure, reliability and validity in a cohort of patients with COPD.

Methods: A total of 137 patients with stable COPD were recruited. Two scales of 4 items each were designed and their structure was verified by exploratory factor analysis and multitrait scaling analysis. Additionally, reliability indices (internal consistency and test-retest) were calculated. Construct validity was analysed by known groups and convergence-divergence.

Results: The questionnaire had 2 scales, with 4 items each, corresponding to the domains of the International Classification of Functioning, Disability and Health "change and maintain the position of the body" and "walk and move". The reliability and internal consistency of the scales were acceptable and the test-retest was excellent with an ICC of 0.86 and 0.94, respectively. The scales showed a moderate association with dyspnoea, health status and muscle strength and a different score among participants with different physical performance in the Short Physical Performance Battery.

Conclusions: The 2 scales of the DIAMO-EPOC questionnaire are one-dimensional and have a solid internal consistency, test-retest stability and validity, allowing the identification of specific areas of limited mobility in patients with COPD.

Keywords: Actividad física; Batería corta de rendimiento físico; Chronic obstructive pulmonary disease; Cuestionario; Disability; Discapacidad; Enfermedad pulmonar obstructiva crónica; Fiabilidad; Mobility; Movilidad; Physical activity; Questionnaire; Reliability; Short Physical Performance Battery; Validez; Validity.