Psychometric properties of the WHO Quality of Life questionnaire (WHOQOL-100) in patients with chronic diseases and their caregivers in China

Objective: To evaluate the psychometric properties of the WHO Quality of Life questionnaire (WHOQOL-100), a multi-dimensional conceptualized, 100-item quality-of-life instrument. Methods: A total of 460 patients in China with chronic diseases (including hypertension, schizophrenia, stroke, end-stage renal disease, head and neck cancer and breast cancer) and 418 family members who were their caregivers were assessed at baseline and one year later. Findings: The WHOQOL 100 had acceptable internal consistency (alpha = 0.76-0.90 across domains). There were strong correlations between the domains of WHOQOL-100 and the dimensions of the General Quality of Life Inventory (alpha = 0.72-0.82 across related domains). Within domains most facet correlations were satisfactory, although some facets correlated more strongly with a domain other than that to which they had been assigned. Principal component analysis produced four factors accounting for 61% of the total variance. Conclusion: The WHOQOL-100 was able to discriminate between the different groups of patients and was sensitive to clinical change in patients' conditions. It proved to be reliable and valid instrument for assessing the quality of life of patients with chronic diseases and their caregivers in China.