Clinical economics and noncoronary vascular disease.

With the evolution of the U.S. health care system toward managed care, there is increasing concern with the economics of health care delivery. Several important basic principles and approaches are reviewed here. First, costs, not charges, must be assessed, and these costs must include both direct medical costs, in the form of resources consumed, and indirect costs, such as productivity losses. Second, the simplest type of analysis, cost-identification analysis, is rarely appropriate to the clinical situation in which interventions with potentially different risks and benefits are being compared. Cost-benefit analysis may be more useful, but accurate assessment of benefits in monetary units is often not possible. Cost-effectiveness analysis expresses costs in monetary units, but quantitates benefits in natural units of outcome, such as survival or altered function. Results are expressed, for example as cost per year of life saved. In the more common clinical situation, however, outcomes include preferences, and the utility of interventions is quantitated in cost per quality adjusted life-year. All of these types of assessment are limited, to some extent, by differences in patient populations and in patient preferences. Probably the greatest contribution from clinical economic analysis occurs in the relatively common situation in which two alternative interventions both have advantages and disadvantages-that is, neither of the choices is both more effective and less expensive. Incremental cost-effectiveness of different interventions can be used instead, and this, empirically, has been shown to have great clinical relevance.