Validation of the World Health Organization Disability Assessment Schedule (WHODAS 2.0) for individuals with asthma.

Purpose: There are no disease-specific tools for assessing the functioning of patients with asthma. This study aims to evaluate the psychometric properties of the Brazilian version of the World Health Organization Disability Assessment Schedule (WHODAS 2.0) in individuals with asthma.

Methods: 101 individuals with asthma responded to the 36-item version of the WHODAS 2.0, Asthma Quality of Life Questionnaire (AQLQ), and Asthma Control Test (ACT). The following psychometric properties were tested: internal consistency, factor structure, and convergent and discriminative validity.

Results: Homogeneity was found between WHODAS 2.0 items and domains, except "Getting along" (Cronbach's α = 0.57). When item "D4.5 Sexual activities" was deleted, the Cronbach's increased to 0.70. Exploratory factor analysis identified four factors (explained variance 56%). There was a strong correlation between the WHODAS 2.0 and AQLQ (r=-0.72) and between the WHODAS 2.0 and ACT (r= -0.59). There was no evidence of the influence of obstruction level (FEV) on functioning.

Conclusion: WHODAS 2.0 is a valid and reliable tool for assessing functioning in individuals with asthma. Exclusion of item D.4.5 Sexual activity increased the homogeneity between the items of the "Getting along" domain. When applied to asthmatics, the WHODAS total functioning score is preferable to the domain-specific scores.