Quality adjusted life years: Looking for consensus
Research Activities, August 2009, No. 348
The quality adjusted life year (QALY) is a widely used measure of both quality and quantity of life that is applicable to all individuals and diseases. The QALY concept is important to outcomes researchers who are attempting to evaluate the efficacy and cost of various health care interventions based on their impact on QALYs. To determine the utility of and need for change in the QALY concept, the International Society for Pharmacoeconomics and Outcomes Research (ISPOR) convened a consensus development workshop, "Building a Pragmatic Road: Moving the QALY Forward" in November 2007. The workshop, which was supported in part by the Agency for Healthcare Research and Quality (HS16841), sought to reach consensus among leaders in the field on the need to refine the QALY concept or substitute an alternative. Subsequently, the presenters prepared a series of articles based on the workshop sessions as a March/April 2009 supplement to ISPOR's journal Value in Health 12(Suppl 1). The first paper provides a background on the use of QALY and the rationale for change. The next six articles address topics ranging from the basics of quality adjusted survival time and an alternate approach to health state valuation to the use of QALY in clinical and patient decisionmaking. The journal supplement also contains two independent editorials on the QALY debate, commissioned by the journal's editor. Brief summaries of the articles and editorials follow.
Smith, M. D., Drummond, M., and Brixner, D. "Moving the QALY forward: Rationale for change," pp. S1-S4.
This paper provides information on the consensus workshop, including background on QALY and how it is estimated. The authors note that some fundamental assumptions underlying the QALY concept have begun to be questioned, for example, whether the preference weights required for estimating the measure should come from patients or the larger health care community. They also discuss how the QALY concept is used by health policymakers and the differences between its use in the U.K. and the U.S.
Weinstein, M. C., Torrance, G., and McGuire, A. "QALYs: The basics," pp. S5-S9.
The authors of this paper provide a QALY primer, describing the assumptions that underlie the measure and explaining the concept of value in health care. They focus on the types of questions for which QALYs may provide part of the answer, such as societal resource allocation/priority setting, personal clinical decisionmaking, and evaluation of ongoing activities or programs. They also explain what is being valued in each case, who is being asked, what to ask, and how to ask about value. Finally, the authors discuss how the evaluated health outcomes are defined.
Nord E., Daniels, N., and Kamlet, M. "QALYs: Some challenges," pp. S10-S15.
This paper discusses a number of problems in estimating QALY values. One problem is getting different values when using different tools (standard gamble, time tradeoff, and rating scale) to estimate health state utilities. Other problems include comparing utility values estimated beforehand by a mix of policymakers, caregivers, and consumers, and those obtained from patient experience. The paper also discusses ethical and societal concerns that QALY may value more, for example, increased lifespan gained by preventing accidents for persons in full health over increases in lifespan due to treatment for patients with chronic illnesses.
Kahneman, D. "A different approach to health state valuation," [Summary] pp. S16-S17.
This paper is a summary of a talk by Daniel Kahneman of Princeton University, given at the consensus development workshop, which builds on presentations he gave at prior ISPOR annual meetings. The author questions whether people developing QALY values can identify the problems that undercut its validity. He suggests an alternative approach using "juries of citizens with varied membership" (economists, health statisticians, patients) to jointly develop a linear scale that can be used to compare health states.
Lipscomb, J., Drummond, M., Fryback, D., and others. "Retaining, and enhancing, the QALY," pp. S18-S26.
The authors review a variety of issues related to what they term the "conventional QALY," with the goal of retaining and enhancing this measure. In particular, they suggest that research be conducted into improving systems that describe health states, valuation methods, and weightings that reduce possible discrimination against the disabled and chronically ill by maximization models using the conventional QALY.
Kind, P., Lafata, J. E., Matuszewski, K., and others. "The use of QALYs in clinical and patient decision-making: Issues and prospects," pp. S27-S3.
The authors discuss the uses of QALY in high-level decisionmaking (for groups of patients or whole populations) and the potential and limitations of its use in decisionmaking for individual patients and their clinicians. At present, QALY is used routinely by payers, managed care organizations, and governmental organizations for making cost-benefit decisions about care for groups of patients, but not in making clinical decisions for (or by) individual patients.
Drummond, M., Brixner, D., Gold, M., and others. "Toward a consensus on the QALY," pp. S31-S35.
This article summarizes eight areas of consensus reached during the workshop, including that QALYs are one (but not the only) health-based input to health and health care decisions, that they can be used at various levels in the health care system, and that distributive fairness needs to be addressed in developing QALY measures. The authors also summarize the current use of QALYs, the challenges of using these measures in some health settings, and research priorities concerning the nature and future use of the QALY.
Garrison, L. P., Jr. "Editorial: On the benefits of modeling using QALYs for societal resource allocation: The model is the message," pp. S36-S37.
In his editorial, the author notes that the workshop articles failed to explore two related issues. First, measures of life quality based on preferences of unaffected individuals can differ markedly from those of people with a chronic condition. Second, the use of QALYs in allocating public resources can differ depending on how much health care is seen as a "free market" activity.
Johnson, F. R. "Editorial: Moving the QALY forward or just stuck in traffic?" pp. S38-S39.
The author of this editorial is critical of the usefulness of the conventional QALY, in part because it ignores the economic principle of diminishing marginal utility, which requires nonlinearity of preferences. He cites an alternate approach developed by the German Institute for Quality and Efficiency in Health Care, which concludes that QALYs are both unethical and unconstitutional within the context of that nation's health care system.