If you had a given disease, how bad would it be? Can we quantify people’s happiness based on different diseases? One way to do this is to measure patient preferences using a concept known as health state utilities. As stated in a recent ISPOR guidelines, health state utilities are “estimates of the preference for a given state of health on a cardinal numeric scale, where a value of 1.0 represents full health, 0.0 represents dead, and negative values represent states worse than death.”
Health technology assessment (HTA) agencies often use health state utilities for making resource allocation decisions. For instance, consider the case of a serious disease that makes people wheelchair bound for multiple years. Would you rather pay for a treatment that could extend healthy individual’s 1 year or a treatment that eliminated their need for a wheelchair but had no effect on survival? If you feel that being in a wheelchair is not too bad (health state utility closer to 1), you would be relatively more likely to choose the treatment that extended people’s life; on the other hand, if you though living in a wheelchair was a horrible fate (health state utility close to 0), then you would be relatively more likely to prefer the treatment that eliminated the need of the wheelchair without any survival gain. The health state utilities are a way to quantify the degree of these preferences.
How are these health state utility data collected?
These health state utilities–often used in economic models–can be collected in a number of ways. For instance,
- Review of published estimates. This approach would conduct a literature review of published literature to identify high-quality health state utility estimates. The review can be targeted or systematic, as some HTA agencies (e.g., Canadian Agency for Drugs and Technologies in Health, Haute Autorité de Santé, and NICE) require a systematic literature review as part of their submission process.
- Prospective data collection in clinical trials. Clinical trials are one easy way for stakeholders to collect health state utilities. There are a number of methodological considerations to consider. For instance, it is important to insure that the data “…captures proﬁles of change around the relevant health states”. Collecting health state utlity data as part of a clinical trial may also be more cost effective.
- Prospective longitudinal or cross-sectional observational studies. “These studies may offer the greatest ﬂexibility in terms of the data that can be collected; and, for many health states, it may be more appropriate to collect HSU data in observational or routine data sets rather than in trials.” These approaches, however, are often expensive and collecting these data may take time.
- Early-access or compassionate-use–type programs, phase 4 studies, registries, and other postlicensing commitments. These studies may better reflect health state utilities in real world settings. For life sciences firms, however, these approaches have significan drawbacks since these studies typically are performed to late to be included in submissions to HTA bodies.
- Vignette studies. “In this approach, detailed descriptions of each health state are developed from different sources of information (e.g., patient and physician interviews, trial data, and published literature) [18–20]. Members of the public are asked to rate these states in a stated-preference experiment (such as time trade-off or standard gamble). These methods are limited because the resulting estimates are entirely dependent on the validity of the vignette descriptions…”
What are common preference based measures used to estimate health state utilities?
These preference measures can be divided into general measures–those relevant for any diesase–and those that are condition-specific. Some examples of general preference based instruments include:
- AQoL, Assessment of Quality of Life;
- EQ-5D, EuroQol ﬁve-dimensional questionnaire
- HUI, Health Utilities Index;
- SF-6D, six-dimensional health state short form (derived from 36-item short form health survey).
Some condition specific examples of preference based measurement instruments include:
- AQL-5D, Asthma Quality of Life Utility Index;
- EORTC-8D, European Organization for Research and Treatment of Cancer cancer-speciﬁc instrument
There is more information in the article on how to estimate health state utilities so do read the whole article.
- Wolowacz, Sorrel E., Andrew Briggs, Vasily Belozeroff, Philip Clarke, Lynda Doward, Ron Goeree, Andrew Lloyd, and Richard Norman. “Estimating health-state utility for economic models in clinical studies: an ISPOR good research practices task force report.” Value in Health 19, no. 6 (2016): 704-719.