RELATIONSHIP BETWEEN PSYCHOMETRIC AND UTILITY-BASED APPROACHES TO THE MEASUREMENT OF HEALTH-RELATED QUALITY-OF-LIFE

This paper summarizes selected evidence pertaining to the relationship between psychometric health status measures and utility/preference measures of health outcome. Few studies contain measures of both health status and utility/preference. The evidence to date suggests that various health status measures are at best only moderately correlated with standard gamble (SG) and time trade-off (TTO) utilities. Results from regression analysis, predicting SG or TTO utilities from combinations of health status scales, typically have an R2 of 0.18 to 0.43. Preferences determined by rating scale methods are more strongly related to health status scores, but correlations are variable ranging from 0.17 to 0.46 and only about 27% to 34% of variance can be explained in regression models. The Quality of Well-Being Scale and other multiattribute preference measures have low to moderate correlations with health status measures (r = 0.03 to 0.71). Health utility/preference measures and psychometric health status scores are only moderately correlated. Health utility and psychometric health status scales may measure different attributes of health. Although both approaches are useful for evaluating medical outcomes, they are not interchangeable indicators of health-related quality of life.