Psychometric validation of the Chinese version of the Illness Perception Questionnaire-Revised for patients with hypertension

Aim. This paper is a report of a study to evaluate the psychometric properties of the Chinese version of the Illness Perception Questionnaire- Revised using the technique of confirmatory factor analysis. Background. The Illness Perception Questionnaire-Revised is the most commonly used instrument for assessing patients' views of illness, and there is good evidence for the psychometric properties of the English version. However, there is inconsistency in the literature about how scores of the Illness Perception Questionnaire-Revised should be used. Method. A cross-sectional survey was conducted in three teaching hospitals in central Taiwan. The Chinese Illness Perception Questionnaire-Revised was administered to a purposive sample of 358 patients with hypertension in 2005-2006. Results. Confirmatory factor analysis provided evidence of satisfactory factorial validity, convergent validity and discriminant validity of the Chinese Illness Perception Questionnaire-Revised. Internal consistency was supported by adequate Cronbach's alphas (ranging 0.67-0.87) and composite reliability (0.57-0.88). The factor structures of the identity and cause subscales were found to be an acceptable fit to the data. The findings of model evaluations supported the seven-factor structure, after removal of six poorly fitting items. Second-order analysis indicated two factors (control and negative illness representation) representing latent constructs underlying the factors of personal control, treatment control, consequence, timeline-cyclic and emotional representation. Conclusion. The Chinese Illness Perception Questionnaire-Revised is a reliable and valid instrument for the measurement of illness perceptions in patients with hypertension.