Psychometric Properties of the World Health Organization Disability Assessment Scale 2.0 among Iranian Cancer Patients

Background: The WHODAS-2 is a disability assessment tool built according to the conceptual framework of the international classification of functioning, disability, and health. This tool is a standard measure of disability dedicated to six specific domains. The aim of this study was to examine the psychometric properties of the World Health Organization Disability Assessment Scale 2.0 among Iranian cancer patients. Method: This study included cancer patients who referred to the Cancer Institute of Imam Khomeini Hospital, Tehran, Iran. For this purpose, we enrolled 320 patients and asked them to complete the questionnaires. Cronbach's a assessed the internal consistency. Pearson's correlation coefficient evaluated the divergent and convergent validity and correlation of WHODAS 2.0 with EORTC QLQ-C30, difficulty of emotion regulation, and co-rumination scales. Moreover, we assessed constructive validity by confirmatory factor analysis using smart PLS software. Result: The results showed that Cronbach's a was 0.91 for the questionnaire and higher than 0.75 for all domains. Furthermore, there was a significant correlation among the WHODAS 2.0 with Cancer EORTC QLQ-C30 (r = 0.85), DERS (r = 0.78), and co-rumination scales (r = 0.71). Conclusion: The version of the WHODAS 2.0 instrument had suitable psychometric properties in the sample of cancer patients. Therefore, it can be used in different populations and samples of cancer patients.