Methodological Research
Valuing health states using Quality Adjusted Life Years
Quality-adjusted life years (QALYs) are becoming a common metric for quantifying health outcomes, as they are able to combine measures of both life expectancy and health-related quality of life (HRQL) into a single summary measure. QALYs are usually calculated by weighting each year of a patients’ remaining life by a HRQL index, which has been referred to as a health state utility, where 1.0 is equivalent to “full health” and 0.0 is equivalent to being “dead”. Health economists have traditionally used techniques such as the time trade-off method on patients or the general public (based on questionnaires involving health state descriptions) in order to estimate preferences for HRQL. However, it is often difficult to directly measure health state utilities as the elicitation techniques often require extensive personal interviews. In practice these values are often obtained from algorithms or value sets developed for multi-attribute instruments such as the EQ-5D for quantifying HRQL.
The research in the School is focused primarily on valuing QALY experienced by patients with diabetes and the impact complications may have on HRQL. Previous research has included valuing the decrement in utility following micro vascular complications such as myocardial infarction and micro vascular included loss of visual acuity. Recent work has focused on the association between measures HRQL and subsequent events including mortality.
Researchers Involved
Publications
Clarke P. Gray A. Holman R. “Estimating utility values for health states of type 2 diabetic patients using the EQ-5D (UKPDS 62)", Medical Decision Making Vol. 22. pp. 340-349, 2002
Clarke PM. Simon J. Cull CA. and Holman RR. Assessing the impact of visual acuity on quality of life in individuals with Type 2 diabetes using the Short Form-36, Diabetes Care 2006 29: 1506-1511.
Hayes AJ, Clarke PM. Glasziou PG, Simes RJ, Drury PL Keech AC. “Can self-rated health be used for risk prediction in patients with type 2 diabetes?” Diabetes Care (accepted 27 Dec 2007)