Where Are the Medicare Part D Claims Data?

Since the inauguration of the Medicare Modernization Act Prescription Drug Benefit (Part D) on 1 January 2006, the Centers for Medicare & Medicaid Services (CMS) has systematically collected prescription drug claims data (known technically as prescription drug event data) from all Part D plans. These data are used to track beneficiary cost-sharing amounts and conduct other payment-related activities (1). However, CMS has not made them available for any other purpose. A proposed regulatory rule issued on 18 October 2006 would give researchers and other federal agencies access to prescription drug event data, but the rule is yet to be released in final form (2). By sequestering prescription drug event data, CMS has seriously hindered the public's right to know about the performance and outcomes associated with the Medicare drug benefit.

Medicare prescription drug event data are essential to any evaluation of the Part D program; however, the data have other important uses as well. The U.S. Food and Drug Administration proposed including Part D data in a new sentinel system to improve drug safety monitoring (3), but this has not yet happened. The Medicare Payment Advisory Commission has repeatedly requested Part D claims data to support its congressionally mandated responsibility to report on the effect of the drug benefit, to no avail (4, 5). The Medicare prescription drug event data represent an essential resource for conducting comparative effectiveness studies of medications used by the …