PQP3: DEFINING CLINICALLY MEANINGFUL CHANGE IN HEALTH-RELATED QUALITY OF LIFE

Abstract

OBJECTIVES: This paper reviews current approaches to defining clinically meaningful change in health-related quality of life (HRQOL). METHODS: Definitions of clinically meaningful change are discussed. Psychometric properties of HRQOL instruments necessary for identifying clinically meaningful change are identified. Two broad methods for identifying clinically meaningful change are contrasted: anchor-based methods and distribution-based methods. Anchor-based methods include forced-choice paradigms, global change ratings, receiver operating characteristic techniques, goal attainment scaling and external event methods. Distribution-based methods include individual effect size, the Guyatt responsiveness index, the Jacobson-Traux reliable-change index (and subsequent variations), standard error of measurement, and hierarchical linear modeling. Strategies for validating clinically meaningful change measures are discussed. RESULTS: Anchor-based and distribution-based methods have both advantages and limitations, and neither appears superior to the other. Anchor-based methods provide a source for external validation, but are dependent on the specific anchors being used. Distribution-based methods provide a statistical basis for decision-making, but may vary on the basis of sample characteristics. CONCLUSIONS: The use of multiple methods to define clinically meaningful change is strongly recommended. Factors to consider in defining clinically meaningful change include the severity of the baseline value, the direction of change, and the importance of the change to the individual.