More than 90 percent of researchers who have published studies favorable to the controversial diabetes drug Avandia had a financial stake in the issue, according to a study conducted by researchers from the Mayo Clinic.
The Mayo Clinic is one of the few research organizations in the United States that does not accept corporate funding.
Sales of GlaxoSmithKline’s bestselling drug Avandia plunged in 2007, after evidence emerged linking the drug to an increased risk of heart attack and death. These reports sparked a debate over the drug’s safety that continues to this day.
In an analysis of more than 200 studies, articles, editorials and letters published in scientific journals since 2007, Mayo Clinic researchers have concluded that financial conflict of interest continues to play a major role in that debate. Fully 87 percent of all authors who expressed positive views about Avandia had financial ties to GlaxoSmithKline, while another 7 percent had ties to other pharmaceutical companies involved with diabetes. Among authors with financial conflicts of interest, only 30 percent “expressed unfavorable views” of the drug.
In contrast, authors who were critical of Avandia were “largely free of identifiable conflicts of interest,” the researchers said.
The conflicts of interest cut both ways. Of 29 authors who recommended the drug Actos as a safer alternative to Avandia, 25 had ties to that drug’s maker, Eli Lilly.
In order to identify conflicts of interest, the Mayo Clinic researchers searched through multiple published works by each given author, as well as conducting investigations on the Internet. This research uncovered that while 47 percent of all authors surveyed had a financial stake in the diabetes drug debate, 23 percent failed to disclose these links. Most of these authors merely remained silent about their conflicts of interest, while three actually lied and said they had none.
“The implication is that there should be better disclosure,” lead researcher Mohammad Murad said. “People [with financial links to companies] should realize they are probably biased, and as readers we should be aware of probable bias.”
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