How much clinical evidence is enough: regulation of medical devices?

In a recent publication, Marcus and colleagues questioned the adequacy of the amount of high level clinical evidence obtained under the current legal framework for U.S. regulation of medical devices (1). Based on a cross-sectional literature review covering the years 2000 through 2004, they identified clinical research publications for 218 unique medical devices of which 99 (45%) were cleared or approved for marketing in the U.S. The clinical studies associated with the 99 devices were mostly case series or level 4 evidence. In addition to several critical methodological flaws of the study, the authors fail to fully appreciate the current legal framework under which medical devices are regulated in the U.S (2,3).