Quality-adjusted life-years QALYs

The most commonly used measure of utility in the health economics literature is the quality-adjusted life year (QALY), which weights longevity by life quality. The most commonly used preference-weighted measure of health-related quality of life in the UK is the EuroQol or EQ-5D (EuroQpl Group, 1990), but there are various other such measures. Utility scores can now be obtained from the 36-item Short Form (SF-36) quality-of-life scale, for example. Also in use are healthy-year equivalents (Mehrez and Gafni, 1989) and disability-adjusted life years (WHO, 2000), although both these measures are different in aim and construction from the QALY and are used less often in evaluations. 

Cost-utility analysis is similar to cost-efFectiveness analysis in approach, but uses utility as the outcome measure. The utility value is a measure that combines preferences for and values of the overall effect of an intervention on survival, physical and mental health, and social function. Utility is combined with estimates of length of life to provide an assessment of quality-adjusted life years (QALYs). As in cost-efFectiveness analysis, incremental cost-utility ratios are calculated to estimate the cost of producing one extra QALY. 

Cost-utility analysis Dollars Quality-adjusted life-years (QALYs)... 

The CUA is a form of cost-effectiveness analysis in which the health outcomes are measured in terms of quality-adjusted life-years (QALYs) gained. The QALY is a measure that associates quantity of life (e.g. survival data and life... 

Thus, it appears that the current practice by analysts to use AWP results in a value for the cost of a drug that is substantially in excess of marginal cost. If the estimated incremental cost per quality-adjusted life year (QALY) using AWP is very low or very high relative to benchmarks of acceptable ratios, or if drug therapy is dominated by another comparator, treatment of cost would not matter in the decision about whether to cover a drug under an insurance plan or include it on the formulary. But over a sizeable range of values reasonably close to the benchmark, the cost estimate used should affect the decision about acceptability of the product. So it seems appropriate to explore the conceptual framework that should be used for such analysis in more detail. 

Economic evaluation compares costs and consequences of alternative health care treatments or programs (Drummond et al. 2005). In one form of economic evaluation, cost-benefit analysis, all costs and consequences are valued in monetary terms. However, in health care it is much more common to use cost-effectiveness analysis, where the difference in cost between alternatives is compared with the difference in outcomes measured in units such as life years gained or quality-adjusted life years (QALYs) gained. 

These preferences for the different disease states, expressed as numbers, are called utilities, and are used to qualitv-adjust or to weight the additional years of survival. The result is a quality-adjusted life-year (QALY) gained. Quality-adjusted life-years gained are also used frequently as the denominator of a cost-effectiveness ratio, as in costs per QALYs gained. 

Cost-utility analysis is used when quality of fife is the most important outcome being examined. This is common in disease states in which how one feels or what one can do is more important than a clinical laboratory value or economic outcome (e.g., chronic diseases such as heart disease, diabetes, arthritis, cancer, or HIV/AIDS). Cost-utility analyses compare the direct and indirect costs of an intervention with some measurable level of humanistic outcome, such quality of life or level of satisfaction. The direct and indirect costs of treatment alternatives again are expressed in monetary terms. The humanistic outcomes associated with each intervention can be expressed as an SF-12 or SF-36 health survey score for quality of life (Ware, 1997), as a satisfaction survey score (Mac-Keigan and Larson, 1989), or as quality-adjusted life-years (QALYs). QALYs represent the number of full years at full health that are valued equivalently with... 

Everyone is familiar with the measurement of the benefit of treatment in saving or extending life, i.e. life expectancy the measure is the quantity of life (in years). But it is evident that life may be extended and yet have a low quality, even to the point that it is not worth having at all. It is therefore useful to have a unit of health measurement that combines the quality of life with its quality to allow individual and sodal decisions to be made on a sounder basis than mere intuition. To meet this need economists have developed the quality-adjusted-life-year (QALY) estimations of years of life expectancy are modified according to estimations of quality of life. 

The CUA is a form of cost-effectiveness analysis in which the health outcomes are measured in terms of quality-adjusted life-years (QALYs) gained. The QALY is a measure that associates quantity of life (for example survival data and life expectancy) with quality of life, by amalgamating them into a single index. One QALY is equal to a year of full life quality. Because of its universal denominator which allows comparisons across divergent areas, CUA is a tool that can (in theory) be used by policy makers... 

Cost utility analysis (CUA)—Uses an outcome measure, which combines longevity and quality of life, usually the quality adjusted life year (QALY), with results expressed in terms of cost per QALY gained. 

Medical intervention costs can be normalized to assess total costs using quality-adjusted life years (QALYs) gained by the intervention. The use of a QALY approach to treatment of critically ill patients with ARP indicates that treating these patients is very expensive relative to other common medical interventions. For example, using 2001 cost values, the treatment of critically ill ARF patients cost per QALY was 168,711, compared to treatment of acute myocardial infarction cost per QALY of 45,000, and the routine treatment of hypertension... 

Quality-adjusted life year (QALY)—A humanistic assessment of quantity and quality of life. An adjusted life year is calculated by multiplying the number of years by the utility of the health state. For patients who have had a moderate stroke, the utility of their health state is usually less than 0.5. This means that it would take 2 years at their health state to equal one year at normal health (utility of 1.0). 

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