The role of prevention in improving the quality of health care by preventing illness, disability, and death through expanded coverage or use of preventive services is a key topic of discussion among those seeking to reform the nation's health care delivery system. Many argue that preventive services have the potential to greatly improve patients' health. They cite, among other things, the burdens of disease and premature death that result from tobacco use, poor diet, and other unhealthy behaviors. Preventive services that improve health outcomes are seen as a means to improve the quality of care provided by the nation's health care system. Chronic diseases place a growing health burden on older Americans, and an increasing cost burden on the Medicare program. According to the Congressional Budget Office (CBO), "without any changes in federal law, total spending on health care will rise from 16 percent of GDP in 2007 to 25 percent in 2025 and close to 50 percent in 2082; net federal spending on Medicare and Medicaid will rise from 4 percent of GDP to almost 20 percent over the same period. Many of the other factors that will play a role in determining future fiscal conditions over the long term pale by comparison with the challenges of containing growth in the cost of federal health insurance programs." Some stakeholders have touted prevention as a means to contain health care costs. Whether expanding coverage or utilization of preventive services would actually save money for Medicare is, however, a matter of continuing debate. Some clinical preventive services may both improve the patient's health and save money for payers. Most clinical preventive services, however, add to health care costs borne by the payer. When effective, these services may nonetheless be considered to provide a good value for their cost; that is, they are cost-effective. Whether or not a preventive measure is cost-effective depends on the type of intervention and the population that is targeted. For example, an expensive screening test that is provided to the general population is likely to be very costly and provide limited clinical benefit if only a small fraction of those individuals would have become ill in the absence of the screening. But a less expensive intervention targeted at a population at high risk for a disease is likely to yield much greater value, and may even yield a net savings to the health care system. In general, Medicare law authorizes the Secretary to cover services for the diagnosis and treatment of illness, while coverage of preventive services (i.e., services provided in the absence of symptoms) has generally required legislation. Although there is no statutory definition of "preventive services" that refers to these services collectively, Medicare law outlines specific coverage criteria for many preventive services, including factors such as the types of screening tests or services covered, and the age or risk profiles to which a service applies (see " Which Preventive Services Does Medicare Cover? "). Over the years, Congress has sought expert advice to determine, for the purposes of Medicare coverage, whether a given preventive service is effective, and whether its clinical use is likely to benefit the patient without posing potential risks from the procedure itself. Current Medicare coverage of preventive services does not always comport with evidence-based recommendations of expert panels such as the U.S. Preventive Services Task Force (USPSTF). Congress provided the first administrative authority for the Secretary of Health and Human Services (HHS) to add coverage of additional preventive services in the Medicare Improvements for Patients and Providers Act of 2008 (MIPPA, P.L. 110-275 ), if, among other things, such a service is recommended by the USPSTF (see " U.S. Preventive Services Task Force (USPSTF) "). A recent USPSTF recommendation regarding screening mammography has refocused congressional attention on the appropriate role of advisory panels with respect to Medicare coverage decisions. This report examines Medicare coverage of clinical preventive services. First, it provides a brief overview of the Medicare program and history of congressional actions that added coverage of various clinical preventive services under Medicare, including, most recently, a comprehensive health assessment for new Medicare beneficiaries, and a new administrative authority of the Secretary of HHS to expand Medicare coverage of preventive services. Next, this report discusses how Medicare makes coverage decisions for its services, including preventive services. The report then discusses several advisory groups—in particular the USPSTF—and their recommendations regarding the effectiveness of clinical preventive services, Medicare coverage of these services, or related matters. Then it discusses two issues: (1) Do clinical preventive services help Medicare control costs? and (2) What is the utilization of Medicare clinical preventive services, and how might it be improved? This report then discusses current legislative proposals to reform the health care system, with respect to provisions regarding Medicare coverage of preventive services. Finally, the Appendix provides a comparison of Medicare coverage of preventive services with USPSTF recommendations for such services. This report will be updated as events warrant. Medicare is the nation's federal insurance program that pays for covered health care services of qualified beneficiaries. It was established in 1965 under Title XVIII of the Social Security Act as a federal entitlement program to provide health insurance to individuals 65 and older, and has been expanded over the years to include permanently disabled individuals under 65. Medicare covers hospitalizations, physician services, prescription drugs, skilled nursing facility care, home health visits, and hospice care, among other services. The program is administered by the Centers for Medicare and Medicaid Services (CMS) in HHS and consists of four distinct parts (A through D). Most persons aged 65 or older (and certain disabled persons under age 65) are automatically entitled to premium-free Medicare Part A which primarily covers hospitalizations. Generally, enrollment in Medicare Part B, which includes coverage of preventive services, is voluntary. All persons entitled to Medicare Part A may enroll in Part B by paying a monthly premium. In order to choose the Medicare Advantage (Part C) option, members must be entitled to Part A and enrolled in Part B. Medicare Part B requires coverage of a number of specified clinical preventive services including a one-time initial preventive physical examination (IPPE); cardiovascular screening; certain periodic cancer screenings; bone mass measurements; diabetes screening, supplies and self-management training; medical nutrition therapy; and glaucoma tests. Medicare Part B also covers vaccines against influenza, pneumococcus, and, for individuals at increased risk, hepatitis B. Medicare Part D covers any FDA-licensed vaccine, when prescribed by a physician. Beneficiaries are responsible for an annual deductible ($155 in 2010) and 20% of the costs of most Part B covered services. (Medicare covers the remaining 80%). However, Medicare law has been amended to waive cost-sharing for some, but not all, Part B covered preventive services. Medicare Advantage (MA, Medicare Part C) offers beneficiaries an alternative way to obtain covered services through private health plans that are paid a per-person amount to provide Medicare covered benefits to enrollees. Participating MA plans must cover all services covered by original Medicare (except hospice), including Part B benefits, but may also offer coverage of additional services and have considerable flexibility in how they apply or waive cost-sharing. In general, MA plans cover some preventive services that original Medicare does not, and cost sharing may be less for such services. In 2008, all MA plans covered routine regular physical exams, in addition to a one-time IPPE. Additional preventive services that some MA plans covered included preventive dental services, vision and hearing benefits, expanded chiropractic and podiatry benefits, and selected health education and wellness benefits. Historically, Medicare has covered services to treat illnesses or injury covering only those expenses for items or services that fall within a defined Medicare benefit category, and excluding coverage of expenses that are "not reasonable and necessary for the diagnosis or treatment of illness or injury or to improve the functioning of a malformed body member...." Specifically, Medicare Part A and Part B excludes coverage of expenses for routine physical checkups as well as cosmetic surgeries, hearing aids, eyeglasses, routine foot care, routine dental care, and most immunizations (except as allowed in statute). Preventive services were among those services categorically excluded from Medicare when the program was first established in 1965. According to the IOM, One rationale for excluding preventive services from Medicare was that they did not fit the traditional insurance model of providing coverage for expenses that are unpredictable (and thus cannot be budgeted) and substantial (and thus are a serious financial burden to individuals and families). IOM further noted that insurers also discouraged coverage for services that were "broad and ill-defined" such as routine physicals and health education or counseling. Until recently, legislation was required to add coverage of a preventive service to Medicare Part B. Since 1980, when Congress required coverage of pneumococcal vaccination, Medicare law has been amended numerous times to add coverage of specified preventive services under Part B. Recently, Congress enacted the Medicare Improvements for Patients and Providers Act of 2008 (MIPPA, P.L. 110-275 ), which gave the Secretary of HHS limited authority to add coverage for new preventive services administratively, beginning in 2009. Table 1 presents Medicare Part B preventive service benefits that have been added in statute. Often with the passage of these laws, Congress also amended coverage of existing benefits, typically expanding eligibility, increasing the frequency of coverage, and/or covering the use of new screening technologies. (Additional information about the frequency and other aspects of current coverage for selected preventive services is provided in the Appendix .) Along the way, Congress has also eliminated beneficiary cost-sharing requirements for some, but not all, preventive services. As with all Medicare benefits, a beneficiary's use of preventive service benefits is optional. Two recent statutory expansions of Medicare preventive services coverage warrant special mention, and are discussed next. They are (1) coverage of an Initial Preventive Physical Examination (IPPE) and health risk appraisal; and (2) administrative authority of the Secretary of HHS to add coverage of new preventive services, under certain conditions.