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 a reliable and valid instrument for assessing the quality of life of patients with chronic diseases and their caregivers in China.