Responsiveness of the EQ-5D to clinical change: is the patient experience adequately represented?

OBJECTIVES

In many economic evaluations and reimbursement decisions, quality-adjusted life-years (QALYs) are used as a measure of benefit to assess effectiveness of novel therapies, often based on the EQ-5D 3-level questionnaire. As only five dimensions of physical and mental well-being are reflected in this tool, significant aspects of the patient experience may be missed. We evaluate the use of the EQ-5D as a measurement of clinical change across a wide range of disorders from dermatological (acne) to life-threatening (metastatic cancers).

METHODS

We analyze published studies on the psychometric properties of the EQ-5D 3-level questionnaire, extracting information on the Visual Analogue Scale versus Index score, Standardized Response Mean, and Effect Size. These are compared with ranges generally accepted to represent good responsiveness in the psychometric literature.

RESULTS

We find that only approximately one in five study populations report subjective health state valuation of patients within 5 percent of the score attributed by the EQ-5D index, and more than 40 percent of studies report unacceptable ceiling effects. In the majority of studies, responsiveness of the EQ-5D index was found to be poor to moderate, based on Effect Size (63 percent poor–moderate) and Standardized Response Mean (72 percent poor–moderate).

CONCLUSIONS

We conclude that the EQ-5D index does not adequately reflect patient health status across a range of conditions, and it is likely that a significant proportion of the subjective patient experience is not accounted for by the index. This has implications for economic evaluations of novel drugs based on evidence generated with the EQ-5D.