Cost per QALY

This approach to defining cost therefore proposes a three-step procedure for the evaluation of new pharmaceutical products. Assume that there is some threshold value V for cost per QALY that appropriately governs resource allocation. 

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. 

Returning to our example, we can now examine the costs per QALYs for treatment A and treatment B. Table 9.3 illustrates these calculations. As the table shows, when calculating the incremental cost per effect (cost-effectiveness ratio) using unadjusted life-years gained, treatment A costs 10000 for that additional year of life. But when we use the QALYs gained we see that this additional QALY actually costs 50 000. 

When presenting a cost per QALY gained figure, it is important to put it in perspective. At what point does the cost for an additional QALY become too high For this answer, the cost of a QALY can be compared to the cost of QALYs in other treatments. Examples of cost per QALY ratios (in 1999 US dollars) include estrogen therapy for postmenopausal women ( 67165), coronary artery bypass graft for single-vessel disease with moderate to severe... 

The results of the application of this model are, among others, that. differences m clinical outcomes exist between levodcpa alone and entacapone phis levodcpa, entacapone substantially improved the amount of time spent with 25% OFF tune, hvmg with 25% OFF time pier day was increased by 0.63 years (or 7.6 months) ova the 5-year time period, and the costs per QALY gained were 9221 and 20986 for total and direct medical costs, respectively. 

Related to the QALY is the ICER, the incremental cost-effectiveness ratio, which is the cost per QALY gained. Table 45.6 shows the estimated ICERs for a range of new drugs submitted to NICE. ° NICE asks whether an intervention is cost-effective and should be funded free at the point of prescription. 

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. 

Resnlts of CUA are also expressed in a ratio, a cost-ntifity ratio (C/U ratio). Most often this ratio is translated as the cost per QALY gained or some other health-state ntifity measnrement. The preferred treatment alternative is that with the lowest cost per QALY (or other health-statns ntifity). QALYs represent the nnmber of fnU years at fnll health that are valned eqnivalently to the nnmber of years as experienced. Eor example, a fnll year of health in a disease-free patient wonld eqnal 1.0 QALY, whereas a year spent with a specific disease might be valned significantly lower, perhaps as 0.5 QALY, depending on the disease. 

QALYs. The use of clopidogrel or ERDP + ASA is associated with higher efficacy but significantly greater costs as well (up to 3 daily). Despite this, both options have been deemed cost-effective when administered to a 65-year-old patient with a history of stroke or TIA for the prevention of recurrence. In a recent analysis, ERDP + ASA was associated with 5000 to 15,000 per QALY (adjusted for the acquisition cost) and clopidogrel was 26,580 per QALY. Any cost per QALY less than 50,000 is thought to be cost-effective. These estimates are extremely dependent on the assumptions made in the model. Cost-effectiveness in an individual patient is much more difficult to discern. 

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... 

The technique is clearly subjective and there is room for much development and validation. Nonetheless, it makes possible some worthwhile comparisons. Table 43.10 shows the treatment costs per QALY produced by different types of... 

---