Validation study of the Chinese version of the Illness Intrusiveness Ratings Scale

Objective: The Illness Intrusiveness Ratings Scale (IIRS) measures illness-induced disruptions to 13 different aspects of lifestyles, activities, and interests. A stable three-factor structure has been well documented in studies conducted in Western countries. However, in Asia, the general validity of this scale has not been examined. Methods: This study investigated the factor structure of the Chinese version of the IIRS in 641 inpatients at a Chinese hospital for cancer patients. The European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30) was also administered and compared with the IIRS. Results: Exploratory principal component analysis identified a two-factor structure, "health and living" and "relationships and personal development", which accounted for 58.65% of the total variance. A "goodness-of-fit" test supported a two-factor solution (P=.070). The IIRS was significantly correlated with scores of every scale in the EORTC QLQ-C30. Conclusion: These findings support the validity of the Chinese version of the IIRS but did not support a cross-cultural equivalence of the factor structure. This study was only performed in hospitalized cancer patients; therefore, further evaluation involving patients with other diseases is warranted. (C) 2011 Elsevier Inc. All rights reserved.