Many clinical trials meant to test the effectiveness of medications or medical devices are small and of questionable quality, according to an analysis published in the Journal of the American Medical Association.
A Fox News report on the study quotes lead researcher Dr. Robert Califf of the Duke Translational Medicine Institute in Durham, N.C., as saying those results are worrisome because doctor groups rely on the studies to set guidelines for preventing and curing diseases.
The study included analysis of more than 40,000 clinical trials registered on the Website ClinicalTrials.gov.
62 percent of the trials involved 100 or fewer patients and two-thirds were conducted at a single research site.
Between 20 and 65 percent of studies failed to randomly split patients between different interventions such as an active drug and a placebo drug. Randomly splitting clinical trial participants is important because results are less likely to be influenced by underlying differences between participants.
Of the trials that cited a funding source, 44 percent were being supported by a drug or device company.
The U.S. Food and Drug Administration’s decision to change the labeling on the Yasmin line of birth control pills recently spotlighted the problematic intersection of medical safety analysis and funding by manufacturers.
The majority of studies found the pills with drospirenone carry up to three times the risk of blood clots compared to contraceptives without it. The only studies that found no such higher risk were those funded by the manufacturer, and even those studies could not eliminate the possibility (within the margin of error) that drospirenone carries a higher risk.
The new labels reflect that higher safety risk.
See the analysis here: http://jama.ama-assn.org/content/307/17/1838.short