Evidence-Based Imaging Guidelines and Medicare Payment Policy

Evidence-based medicine is a key component of recent efforts to improve the quality and cost-effectiveness of clinical practice. The past 20 years have seen the development and dissemination of numerous clinical guidelines, critical pathways, clinical protocols, appropriateness criteria, and the like. Although the names vary, the common theme is the use of scientific evidence and expert opinion to specify “best practices” for the evaluation and treatment of a given medical condition, with the ultimate goals of improving the quality of medical care and controlling costs (Garber 2001; Institute of Medicine 2001; Adams and Corrigan 2003). In the United States, health policy is ultimately implemented through the payment determinations of public and private insurance carriers. Thus, financial incentives must be aligned with clinical best practices to encourage the provision of cost-effective medical services. This is especially important for the Medicare program, which has tremendous influence by virtue of its own buying power and as an exemplar for private payers. This study examines the consonance between evidence-based guidelines and Medicare coverage policies. Specifically, we analyze the relationship between established appropriateness criteria for neurologic imaging procedures and Medicare Part B payment determinations. The primary research question is whether Medicare is more likely to pay for imaging procedures as the level of appropriateness assigned by an expert panel of physicians and neuroscientists increases. Besides having comprehensive appropriateness guidelines already available, imaging is important to study because it accounts for a substantial portion of spending for physician services. Growth of imaging is of particular concern to the Medicare program, with costs for services under the Part B physician fee schedule having risen by nearly 90 percent between 1999 and 2004, from $5.7 billion to $10.9 billion (Hackbarth 2006). Moreover, expenditure for imaging is projected to accelerate if current trends in technology development, complexity, and volume continue (Medicare Payment Advisory Commission 2005a, b). The appropriateness ratings come from evidence-based guidelines for neurologic imaging procedures developed by an expert committee empaneled by the American College of Radiology (ACR) beginning in 1993 (ACR 2005). These ratings, specified for various medical conditions and imaging procedures, were mapped onto the International Classification of Diseases, ICD-9-CM (2005) and the Common Procedural Terminology, CPT (American Medical Association 2005), code sets. We then added the payment determination for the CPT/ICD-9-CM code pair by the carrier who processes claims for Medicare Part B services in Florida and Connecticut. The resulting analytic data set includes 2,510 observations, each of which represents a medical condition/imaging procedure combination, along with the associated appropriateness rating and Medicare payment determination. By comparing appropriateness ratings produced by a formal physician consensus process with information about Medicare payment determinations, this study provides insight into the extent to which Medicare's policies about whether or not to pay for imaging services are consistent with evidence-based appropriateness criteria. The results of this study have implications for the current policy interest in pay-for-performance initiatives. Recently, the Medicare Payment Advisory Commission (2005c) recommended that a portion of providers' payments be based on quality of care, with quality to be assessed by evidence-based, standardized, and accepted measures. Our study suggests that, in addition to paying more for higher quality services, Medicare also should review existing payment determinations in light of current evidence-based standards. The appropriateness criteria we analyzed, cover all diagnostic radiology procedures that might conceivably be performed for a given condition or symptom, including those having low appropriate scores. Therefore, the results of this study lend themselves to some initial recommendations regarding Medicare payment determinations for neurologic imaging procedures.