A taxonomy of the uses of health-related quality-of-life instruments in cancer care and the clinical meaningfulness of the results

Abstract

Objectives: To propose a taxonomy of psychometrically based, health-related quality-of-life instruments related to three levels of decision-making of health care: the macro, meso and micro levels. The choice of appropriate health-related quality-of-life instruments for each level of desired decision making in various clinical settings is illustrated. A secondary objective was to describe solutions for some of the difficulties inherent in the interpretation of the results of health-related quality-of-life assessment.

Design: The three main levels of clinical decision making are listed and the instruments used most frequently in cancer clinical trials are reviewed from the medical literature.

Proposals: Generic and utility-based instruments are likely to be the most valuable at the macro level of decision making, whereas condition-specific, disease-specific, and situation-specific instruments are most useful for decision making at the meso and micro levels. A determination of the proportions of patients who have reached a meaningful change in health-related quality-of-life scores (eg, > or =10 for scales of 1-100) over a standard period is a rational approach to interpreting the significance of changes in scores.

Conclusions: Awareness of the level of decision making that is involved in the clinical assessment of health-related quality of life can be helpful in choosing instruments that are appropriate for various clinical settings. Some of the difficulties in interpreting the meaning of changes in health-related quality-of-life scores can be overcome by comparing the proportions of patients who have achieved a preset magnitude of change.