Reliability and Validity of the Korean World Health Organization Quality of Life (WHOQOL)-BREF in People With Physical Impairments

OBJECTIVE To identify the validity and reliability of the Korean version World Health Organization Quality of Life Assessment (WHOQOL)-BREF among people with physical impairments living in a community. METHODS Participants listed in the community-based rehabilitation project were recruited from 45 public health centers. People with brain lesions or physical disabilities were selected. Respondents (n=750) filled out the Korean WHOQOL-BREF questionnaire. Obtained data were analyzed statistically to assess the internal consistency as well as the construct and discriminant validity. An exploratory factor analysis was also performed. RESULTS Cronbach's α for the total score was 0.839. The value for each domain ranged from 0.746 to 0.849. Pearson correlation coefficient between each domain ranged from 0.539 to 0.717. The highest correlation was between the psychological and physical domain. The item-domain correlation indicated a significant correlation with their original domains. A multiple regression analysis of each domain with two overall questions was performed. The psychological domain made the strongest contribution with the overall quality of life (unstandardized coefficient B=0.065, r(2)=0.437). When general health satisfaction was considered as a dependent variable, the physical domain most strongly contributed to the variable (unstandardized coefficient B=0.081, r(2)=0.462). Exploratory factor analysis yielded four factors in the WHOQOL-BREF, accounting for 55.29% of the variability. To assess the discriminant validity, a comparison of each domain with Modified Barthel Index (MBI) was conducted. There were highly significant changes across the MBI scores with the WHOQOL-BREF domains (p<0.001). CONCLUSION Korean WHOQOL-BREF is a valid and reliable tool to measure the quality of life for people with physical impairments. It has good internal consistency, construct validity and discriminant validity for the population. Further study with a stratified sample is needed.