Development and psychometric testing of the Hemophilia Well-being Index.

BACKGROUND: Hemophilia experts have recommended that screening tools should be introduced into clinical practice to assess patients' needs and perceptions.
PURPOSE: The present work aims to describe the development of a brief instrument for the assessment of subjective well-being of men with hemophilia within an international study involving participants from 10 countries.
METHODS: Several steps were implemented toward achieving this objective: (1) literature review; (2) semistructured interviews in different Ibero-American countries; (3) exploratory qualitative content analysis of the interviews; (4) definition of the construct being evaluated; (5) generation of preliminary items; (6) interjudgment ratings of the items, by both patients and experts, to assess comprehension and review items; and (7) psychometric testing of an international sample of 342 patients with hemophilia.
RESULTS: Exploratory qualitative study allowed the development of an initial pool of items which address salient life domains related to well-being. Interjudgment ratings led to improvements in the wording and comprehensibilty of the preliminary pool of questions. Psychometric testing allowed items to be reviewed according to empirical criteria. The assessment of the underlying structure of the questionnaire by exploratory factor analysis (generalized least squares) showed a unidimensional model explaining 59.7 % of variance. Adequate internal consistency (0.91) and test-retest reliability (0.82) were observed for the instrument. Associations with other outcome measures and clinical indicators also provided a range of evidence for the instrument's validity.
CONCLUSIONS: This study presents a new disease-specific tool which is able to assess subjective well-being in hemophilia patients.The instrument is available in Spanish, Portuguese (Brazilian), and English language versions for use in future research.