Evaluation of measurement properties of the Impact of Weight on Quality of Life-Lite (IWQOL-Lite) instrument among Chinese overweight and obese populations

Abstract

Abstract Purpose To evaluate measurement properties of the Impact of Weight on Quality of Life-Lite (IWQOL-Lite) instrument among Chinese overweight and obese populations. Methods A representative sample of Chinese overweight and obese populations was recruited stratified by age, sex, residence and body mass index (BMI). Social-demographic characteristics, self-reported EQ-5D-5 L and IWQOL-Lite responses were collected through the online survey. Test-retest reliability was assessed using intraclass correlation coefficient (ICC) among a subgroup of the total sample. Structural validity was evaluated by confirmatory factor analysis (CFA). Convergent validity and known-group validity were examined using Spearman’s rank correlation and effect sizes, respectively. Results A total of 1000 respondents (48% female; mean age: 51.7 years; mean BMI: 27.4) were included in this study. Ceiling and floor effects of the IWQOL-Lite were 5.4% and 0.67%, respectively. The ICC between the two tests was 0.992 for IWQOL-Lite among the subgroup (N = 150). The results of the CFA suggested that the five-factor model had an acceptable structural validity (GFI = 0.894, CFI = 0.960, TLI = 0.957, RMSEA = 0.054 and SRMR = 0.033). The Spearman’s rank correlation (range: 0.413–0.611) indicated a satisfactory convergent validity. The effect sizes values of IWQOL-Lite total score and different dimensions were moderate. Conclusions The IWQOL-Lite has been demonstrated to have satisfactory validity and reliability in measuring the HRQoL of Chinese overweight and obese populations. Further research is needed to confirm the sensitivity and responsiveness.

Keywords

• Health-related quality of life
• IWQOL-Lite
• Measurement properties
• Overweight
• Obesity
• China