The QALY Model Upside-Down

Leiden, The Netherlands – The quality-adjusted life years (QALY) model is defined, in its most basic form, as life duration multiplied by an index in the 0-1 range representing the patients’ quality-of-life. The hazard function is a key concept in the statistical analysis of life duration, representing the risk of death at any moment in time.

A researcher at Astellas Pharma Global Development Europe has explored a new representation of the QALY model that could allow classical quality-of-life utilities to be translated into thresholds of short-term excess mortality risk tolerated by a subject for improvements in their quality-of-life.

In the new research study, “Quality-of-Life–Adjusted Hazard of Death: A Formulation of the Quality-Adjusted Life-Years Model of Use in Benefit-Risk Assessment,” Alberto Garcia-Hernandez, Associate Biostatistics Director at Astellas Pharma Global Development Europe, introduces the concept of the quality-of-life adjusted hazard of death.  He defines this as the increased hazard of death that a subject is willing to accept to improve their chronic health status. It is proven that, if the assumptions of the linear QALY model hold, the excess mortality rate tolerated by a subject for a chronic health improvement is inversely proportional to the expected remaining lifetime. This result allows using trade-offs of life duration to calculate thresholds of tolerated mortality risk during a short period of time, thereby avoiding direct trade-offs using small probabilities of death during the study, which is known to lead to bias and variability.

Says Garcia-Hernandez, “This work reveals the need for further collaboration between statisticians, especially those in the survival analysis field, and experts on utility theory and behavioral economics, in order to bridge the gap between the analytical methods used to evaluate a drug’s performance for regulatory approval and the models used for decision making in heath technology evaluations.”

The full study is published in Value in Health.

Value in Health (ISSN 1098-3015) publishes papers, concepts, and ideas that advance the field of pharmacoeconomics and outcomes research as well as policy papers to help health care leaders make evidence-based decisions. The journal is published bi-monthly and has over 8,000 subscribers (clinicians, decision makers, and researchers worldwide).

International Society for Pharmacoeconomics and Outcomes Research (ISPOR) is a nonprofit, international, educational and scientific organization that strives to increase the efficiency, effectiveness, and fairness of health care resource use to improve health.

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