ABSTRACT
In this chapter, the rationale for collecting quality of life (QoL) data will be discussed, including the controversies surrounding how they should be measured and whether disease-specific or generic health-related quality of life (HRQoL) measures are more suitable for economic evaluation. This is then followed by showing how a commonly cited generic measure in economic evaluations, the EuroQol EQ-5D-3L (EQ-5D), is used in practice, and estimating patient-level EQ-5D data using mapping functions when such data have not been collected in a clinical trial. The quality-adjusted life year (QALY) is then described, with some practical examples of how it is derived under various scenarios. Quality-Adjusted Time Without Symptoms or Toxicity (Q-TWiST) is also discussed, followed by a discussion of statistical and trial design issues relating to HRQoL in the context of an economic evaluation.
