Many of the studies on which Food and Drug Administration reviewers base their premarket approval of cardiovascular devices are inadequately rigorous and prone to bias, according to researchers at the University of California at San Francisco.
Weaknesses seen in FDA's device-approval methods
In a newly published Journal of the American Medical Association article, "Strength of study evidence examined by the FDA in premarket approval of cardiovascular devices," UCSF researchers looked at the FDA's summaries of safety and effectiveness data for 78 high-risk cardiovascular devices that received premarket approval between January 2000 and December 2007. Researchers found that efficacy and safety claims on 65% of those devices were supported by just a single study, and in many cases those studies were prone to bias due to their design. For example, only 27% of the studies were randomized and only 14% were blinded.
The authors also found that 78% of the studies had a discrepancy between the number of patients enrolled and the number analyzed. In most of those cases (93%) the number analyzed was fewer than originally enrolled. That discrepancy can introduce bias because patients with less favorable outcomes may be lost to follow-up and, as a result, safety concerns were unreported, the authors said.
Researchers concluded that the FDA should look to require more rigorous scientific standards for the studies it reviews as a part of premarket approval applications for high-risk medical devices.
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