If you watched the news at all over the past week you probably saw CNN‘s Sanjay Gupta‘s confrontation with disgraced doctor Andrew Wakefield. He, as you may recall was the author of the 1998 study that linked autism to some childhood vaccines and set off a worldwide scare for parents.
In the intervening years there have been countless lawsuits against vaccine manufacturers and millions of children who, perhaps needlessly, have gone unvaccinated. Recently, an investigative report published in the British Medical Journal called the original study an elaborate fraud.
So, is Dr Wakefield alone in manipulating clinical trial data? Can we rely on other clinical studies to provide us with the truth?
No, not according to researchers at Johns Hopkins. In a report published January 4th in the Annals of Internal Medicine the authors concluded that the vast majority of published clinical trials of a given drug, device or procedure are routinely ignored by scientists conducting new research on the same topic.
Trials being done may not be justified, because researchers are not looking at or at least not reporting what is already known. In some cases, patients who volunteer for clinical trials may be getting a placebo for a medication that a previous researcher has already determined works or may be getting a treatment that another researcher has shown is of no value. In rare instances, patients have suffered severe side effects and even died in studies because researchers were not aware of previous studies documenting a treatment’s dangers.
Not surprising then that they go on to say, “the failure to consider existing evidence is both unscientific and unethical.”
The report argues that these omissions potentially skew scientific results, waste taxpayer money on redundant studies and involve patients in unnecessary research.
Conducting an analysis of published studies, the Johns Hopkins team concludes that researchers, on average, cited less than 21% of previously published, relevant studies in their papers. For papers with at least five prior publications available for citation, one-quarter cited only one previous trial, while another quarter cited no other previous trials on the topic. Those statistics stayed roughly the same even as the number of papers available for citation increased. Larger studies were no more likely to be cited than smaller ones.
“The extent of the discrepancy between the existing evidence and what was cited is pretty large and pretty striking,” said Karen Robinson, Ph.D., co-director of the Evidence Based Practice Center (EPIC) at the Johns Hopkins University School of Medicine and co-author of the research. “It’s like listening to one witness as opposed to the other 12 witnesses in a criminal trial and making a decision without all the evidence. Clinical trials should not be started — and cannot be interpreted — without a full accounting of the existing evidence.”
The Hopkins researchers could not say why prior trials failed to be cited, but Robinson says one reason for the omissions could be the self-interest of researchers trying to get ahead.
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