special subjects
Economic Analyses in Clinical Decision Making
Cost Benefit Analysis in Clinical Decision Making
Simple analysis of the economic consequences of outcomes (cost-benefit analysis) depends on assumptions about the perceived dollar value of prolonged life and improved health. Such assumptions are often arguable and rarely straightforward. Furthermore, although such analyses determine whether a given strategy saves costs or requires the net expenditure of resources, they do not indicate whether the expenditures are worthwhile. tracks medical costs and health outcomes separately. Both outcome measures can be strongly affected by the perspective and duration of the analysis and by the underlying assumptions. Comparison of the costs and health outcomes of 2 management strategies results in 1 of 9 pairings (see table Cost-Effectiveness Comparison of Management Strategies A and B ). When health outcomes are equivalent (center column), the choice should be based on cost; when costs are equivalent (center row), the choice should be based on outcome. When one strategy has better outcomes The marginal cost-effectiveness ratio is the additional cost of a strategy divided by the additional health outcome it achieves and thus pertains to the situation in which there is a choice between≥2 effective management strategies. Greater health improvement for a given resource expenditure is derived when the ratio is lower. For policy analysis, the most common measure of effectiveness is the Quality-adjusted life year (QALY) , making the units of the corresponding marginal cost-effectiveness ratio “additional dollars spent per QALY gained.” However, the marginal cost-effectiveness ratio has been criticized because older patients or patients with life-limiting comorbidities have a smaller potential gain in survival from a treatment and therefore have a higher (less advantageous) cost-effectiveness ratio. For example (see table Calculating a Marginal Cost-Effectiveness Ratio , Analysis 1), consider no antiarrhythmic therapy vs prophylactic use of an implantable cardioverter-defibrillator (ICD) for patients who have survived several months after an acute anterior MI and who have a mildly depressed ejection fraction (between 0.3 and 0.4). ( therapy, is available. This therapy is less expensive but also less effective than ICD. The effect of adding this third intermediate strategy is noteworthy because marginal cost-effectiveness ratios are calculated sequentially when there are multiple strategies (see table Calculating a Marginal Cost-Effectiveness Ratio , Analysis 2). The marginal cost-effectiveness ratio of 