Assessing disability in patients with rheumatic diseases: translation, reliability and validity testing of a Greek version of the Stanford Health Assessment Questionnaire (HAQ).

The purpose of this study was to translate into the Greek language the HAQ, validate its psychometric, and also, to assess the degree to which questions in the scale did address common themes, using exploratory factor analysis. HAQ has been translated into Greek (HAQ-GrV), applied to 53 patients with rheumatic pathology and validated as follows: Cronbach's alpha for the estimation of the internal consistency, and the assessment of test-retest reliability, Spearman's rho for the assessment of concurrent validity, and confirmatory factor analysis. The results showed the following: (a) The HAQ-GrV demonstrated very good internal consistency (alpha: 0.90), (b) test-retest scores produced no significant difference (P = 0.07). Spearman's rho ranged from 0.64 to 0.90 for each item. (c) Spearman's rho between HAQ-GrV and HADS was 0.31 (P < 0.05). (d) Factor analysis identified five factors with Eigen values ranging from 1.26 to 6.98, explaining totally 69.4% of the variance.