Cardiovascular Devices Often Approved Without Adequate Studies

Premarket approval (PMA) of cardiovascular devices by the U.S. Food and Drug Administration (FDA) is often based on studies that lack adequate strength or may have been prone to bias, claims a new report.

Researchers at the University of California, San Francisco (UCSF; USA) conducted a systematic review of 123 summaries of safety and effectiveness data (SSEDs) for 78 PMAs for high-risk cardiovascular devices that received PMA between January 2000 and December 2007, examining the methodological characteristics and primary end points. The researchers found that of the 78 PMAs, 65% were supported by just a single study. Of the 123 studies, only 98 SSEDs (80%) reported the number of participants enrolled; only 27% were randomized, and just 14% were blinded. In the SSEDs, there were 157 primary end points for which both the number enrolled and analyzed were stated; of these, 122 (78%) had a discrepancy between the number enrolled and those analyzed.

The researchers explained that the discrepancies between the number of enrolled patients and the number analyzed for primary end points may introduce bias, because patients with less favorable outcomes may be lost to follow-up, and safety concerns may underlie this missing data. The researchers also found that of the 213 primary end points reported in the SSEDs, the results of 15% were noninterpretable. The most common reason was that no target goal for device performance was stated (78%), and in one instance, the results were not stated. The report was published in the December 23, 2009, issue of the Journal of the American Medical Association (JAMA).

"The emphasis at the FDA in the last 17 years since the Prescription Drug User Fee Act has been rapid approval of new drugs,” said lead author Sanket Dhruva, M.D., and colleagues of the division of cardiology. "New surgical operations do not require FDA approval, and new devices, which are nearly always implanted, are between surgical operations and drugs on the FDA approval continuum.”

SSEDs are intended to present a reasoned, objective, and balanced critique of the scientific evidence, which served as the basis of the decision to approve or deny the PMA.

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