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

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). 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). 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