Psychometric Evaluation of the Malay Version of the Impact of Weight on Quality Of Life-Lite (IWQOL-LITE) Questionnaire

ABSTRACT

Background: The availability of obesity specific quality of life measurement tool is limited. The Malay version of Impact of Weight on Quality of Life-Lite is an obesity specific quality of life questionnaire which has been translated for use in Malaysia. The aim of this study is to evaluate the validity and reliability of this tool to measure quality of life among different body mass index (BMI) groups.Methods: One hundred and twenty subjects with different BMI categories attending an outpatient government clinic participated in this study. The translated Malay version of IWQOL-Lite was used for assessment. The validity of this questionnaire was examined using content validity, criterion validity and construct validity. Reliability analyses used in this study were internal consistencies and test-retest reliability. Results: The Malay version of IWQOL-Lite showed good psychometric properties whereby the content validity was sufficient as measured by expert panels. The mean score of all IWQOL-Lite domains were able to discriminate between different BMI groups. Good internal consistency was demonstrated by Cronbach alpha of 0.936. Test-retest reliability ranged from 0.828 to 0.932. The physical function score (IWQOL-Lite) correlated positively with Physical Component Summary of Short Form-36 questionnaire. Exploratory factor analysis found that the questions loaded on five domains. Conclusion: The results suggest that the Malay version of IWQOL-Lite is a valid and reliable tool to measure quality of life among obese and overweight subjects in Malaysia.