Activity limitation and participation restrictions of breast cancer patients receiving chemotherapy: psychometric properties and validation of the Chinese version of the WHODAS 2.0

This study sought to determine the psychometric properties of the Chinese version of the World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0) in a sample of 402 primary breast cancer patients receiving chemotherapy after surgery. Four-hundred and two subjects were interviewed with the Chinese version of the WHODAS 2.0. Patients also completed the Functional Assessment of Cancer Therapy-Breast (FACT-B). Internal consistency reliability was measured by Cronbach's alpha. Spearman correlation coefficients between total scores and subscales of FACT-B and WHODAS 2.0 were examined to get the convergent validity. Independent sample t test was applied to test discriminant validity by comparing the difference of disability scores for different degree of relevant symptoms. The factor structure of the WHODAS 2.0 was examined by Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis. The Chinese version of the WHODAS 2.0 showed satisfactory internal consistency (r, 0.72-0.92), convergent validity and discriminant validity. After 4 items(item D2.2: standing up; D3.3: eating; D4.5: sexual activities; and D6.3: living with dignity) were excluded, EFA identified seven separate factors for 'Self-care and Household activities,' 'Getting along with people,' 'Getting around,' 'Understanding,' 'Communicating,' 'Participation in society' and 'Family burden'(explained variance 72.13 %). The reduced model also presented the best fit [Confirmatory Fit Index = 0.914, Tucker-Lewis Index = 0.900, Root Mean Square Error of Approximation = 0.069] compared with the model suggested by EFA and hypothesized a prior. Overall, the Chinese version of the WHODAS 2.0 is a reliable and valid instrument for measuring activity limitation and participation restrictions in Chinese breast cancer patients receiving chemotherapy.