Cost-effectiveness analysis: some clarifications.

M. G. Myriam Hunink, MD, PhD In view of the ever-increasing health care expenditures, number of uninsured patients, regional variations, and disparities in health care outcomes, a plea for a national program in the United States to study comparative effectiveness and cost-effectiveness of health care interventions was made recently (1). Similar programs exist in many other countries; the United Kingdom National Institute for Clinical Excellence program is probably the best established and most effective (2). In this light, cost-effectiveness analysis of diagnostic imaging deserves attention. Diagnostic imaging is one of the fastestgrowing areas in health care expenditures, with an annual growth rate of more than 20%, mainly because of advances in imaging technology and an aging population. Advanced imaging technologies account for only 15% of the total number of imaging procedures; however, they account for 50% of the overall radiology costs per patient (3). As imagers, we must show that these imaging procedures are justified by an improvement in outcome, or we must curb the increase in cost. We are accountable for the imaging procedures we perform, and we need to provide imaging-related cost-effectiveness information to optimize the imaging choices made. So, where do we stand in providing such information? In this issue of Radiology, Otero et al (4) critically reviewed imaging-related cost-effectiveness analyses published between 1985 and 2005 by using an existing registry of costeffectiveness analyses and published recommendations for cost-effectiveness analyses performed in the United States (4,5). They determined quantity and quality trends of published cost-effectiveness analyses related to diagnostic imaging or image-guided therapy. Their results show that there has been a substantial increase in the number of such analyses accepted for publication. The overall quality of analyses, however, did not increase. In this editorial, I would like to clarify some of the findings of Otero et al. Otero et al (4) found that over a 10-year period, there was a sixfold increase in the annual number of imagingrelated cost-effectiveness analyses performed. This increase should be compared with the threefold increase in health care cost-effectiveness analyses performed in the same period and a 1.5-fold increase in the medical literature in general. In spite of this seemingly large increase, the absolute number of well-performed imaging-related cost-effectiveness analyses in the second period analyzed (1996–2005) was still low (an average of 9.4 articles per year). In the 1990s, a U.S. panel of experts was convened; this panel published a set of recommendations on how costeffectiveness analyses should be performed. In particular, the panel recommended a reference case analysis in which a standard approach would be used to compare cost-effectiveness analyses. Only when analyses are comparable can they be used to guide prioritization of health care interventions in the face of limited resources. Otero et al used the standards of the U.S. panel to judge the quality of the retrieved studies, regardless of whether they were performed in the United States or elsewhere. In countries other than the United States, other specific national recommendations frequently exist for cost-effectiveness analyses. Differences in the recommendations between countries are usually related to the perspective of the analysis, the appropriate discount rate, whether to use a different discount rate for effectiveness versus cost, and which costs should be included. For example, in the United Kingdom, it is currently stanPublished online 10.1148/radiol.2493081479