Factor structure and reliability of the Hungarian version of the Illness Intrusiveness Ratings Scale Invariance across North American and Hungarian dialysis patients

Objectives: The objectives of this study were to compare the factor structure and to assess the reliability of the Hungarian version of the Illness Intrusiveness Rating Scale (IIRS), testing internal validity and employing simultaneous confirmatory factor analysis (SCFA) in two large samples of North American versus Hungarian patients with end-stage renal disease (ESRD). Methods: Translation was conducted according to current recommendations. Following pilot testing, 365 maintenance haemodialysis patients completed the scale. Hungarian data were compared with IIRS data from North American ESRD patients undergoing maintenance hemodialysis to evaluate item bias (Group x Item ANOVA). Results: Confirmatory factor analyses indicated a good fit between the previously hypothesized three-factor model ("relationships and personal development", "intimacy", and "instrumental" life domains) of the original English version and the Hungarian translation. Although statistically significant (P< .05), the effect size for the Groups x Items interaction was not substantial. Internal consistency was very good (Cronbach's alpha = .80) for the total score, and, although somewhat lower than ideal, it was still in the acceptable range for the subscales (.64- .67). These numbers are similar to values reported for the original English version. Test-retest reliability was also acceptable. Conclusion: The Hungarian translation of the IIRS has the same three-dimensional factor structure as the original English-language version does. Furthermore, it is sufficiently reliable for research applications. These features satisfy important requirements of cultural equivalence. (Original abstract)