Validity of the 12-item World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0) in individuals with Huntington disease (HD).

PURPOSE: The reliability and construct validity of the 12-item World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0) were examined in individuals with Huntington disease (HD).

METHODS

We examined factor structure (confirmatory factor analysis), internal consistency reliability (Cronbach's alpha), floor and ceiling effects, convergent validity (Pearson correlations), and known-groups validity (multivariate analysis).

RESULTS

Results of a confirmatory factor analysis replicated the six-factor latent model that reflects the six separate scales within the WHODAS 2.0 (understanding and communicating; getting around; self-care; getting along with others; life activities; participation). Cronbach's alpha for the scale was 0.94, suggesting good internal consistency reliability. The WHODAS demonstrated a ceiling effect for 19.5 % of participants; there were no floor effects. There was evidence for convergent validity; the WHODAS demonstrated moderate significant correlations with other general measures of health-related quality of life (HRQOL; i.e., RAND-12, EQ5D). Multivariate analyses indicated that late-stage HD participants indicated poorer HRQOL than both early-stage HD and prodromal HD participants for all HRQOL measures.

CONCLUSIONS

Findings provide support for both the reliability and validity of the WHODAS 2.0 in individuals with HD.