Reliability, internal consistency, and validity of the World Health Organization disability assessment schedule (WHODAS) 2.0 among adults with heart failure

Background: Heart failure (HF) imposes significant disability. The World Health Organization Disability Assessment Schedule (WHODAS) 2.0 is a generic instrument that measures disability. Although it has been used in HF, no previous study has investigated its measurement properties in this group. Objective: To assess the test-retest reliability, internal consistency, convergent, and discriminant validity of WHODAS 2.0 in individuals with HF. Methods: We conducted a cross-sectional study that included individuals with HF treated at the outpatient cardiology center. Data included sociodemographic and clinical (e.g., New York Heart Association - NYHA) characteristics, estimated functional capacity (Duke Activity Status Index - DASI), quality of life (Minnesota Living with Heart Failure Questionnaire - MLHFQ), and disability (the WHODAS 2.0 36-item version). We assessed associations, using Pearson's correlation coefficient or the Kruskal-Wallis test, between the WHODAS 2.0 scores and the MLHFQ, DASI, and NYHA. The WHODAS 2.0 results were collected again seven days after the initial assessment for reliability (intraclass correlation coefficient - ICC). Results: Participants were 100 people with HF (M age = 57.8 +/- 14 years, 57 % men), of whom 84 % were literate. The WHODAS 2.0 was reliable (ICC = 0.789) and had good internal consistency (Cronbach's alpha >0.7 in all domains). Convergent validity was observed through moderate correlations with DASI and MLHFQ and discriminant validity with statistically different results according to NYHA classes. Conclusion: WHODAS 2.0 is a reliable, consistent, and valid instrument for measuring disability in individuals with HF. Further research is needed to evaluate other properties, such as its responsiveness to interventions.