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

Abstract

PurposeTo evaluate measurement properties of the Impact of Weight on Quality of Life-Lite (IWQOL-Lite) instrument among Chinese overweight and obese populations.MethodsA 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.ResultsA 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.ConclusionsThe 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.