Assessing health-related quality-of-life and health state preference in persons with obesity: a validation study.

The objective of this study was to assess the reliability, validity and responsiveness of a new health-related quality-of-life (HRQOL) measure containing global and obesity-specific domains and an obesity-specific health state preference (HSP) assessment. A total of 417 obese and 'normal' weight individuals completed these assessments. Internal consistency and test-retest reliability were demonstrated, with Cronbach's alpha, intraclass correlation coefficient and kappa values well above the acceptable level for most scales. Construct validity hypotheses were confirmed by examining scale correlations. The normal weight individuals reported statistically significantly better functioning and well-being on the majority of the HRQOL scales and HSP than obese individuals. Guyatt's statistic of responsiveness was moderate to high for all the scales and items in the weight-loss and weight-gain groups; however, many of the scales and items in the weight-stable group also displayed responsiveness. The results of this study support the reliability and validity of these assessments. However, further testing is needed to evaluate the responsiveness of both assessments in a weight-stable group.