[Paleopsych] Discover: A third of medical research wrong?
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Tue Jan 3 22:35:59 UTC 2006
A third of medical research wrong?
November 16, 2005 | Biology & Medicine
The latest medical research is wrong about one-third of the time, that is...
according to the latest medical research. A survey of 49 highly cited
studies by epidemiologist John Ioannidis found the results of 14 studies
contradicted or downplayed by later research. Ioannidis' survey raises some
questions. Is there a fundamental flaw in medical research, or is this just
of scientific progress?
Problems occurred most often in studies that did not use randomized samples
five out of six were contradicted. A group that includes two high-profile
of preventive therapies for coronary-artery disease. One study recommended
hormone replacement therapy for post-menopausal women -- a treatment that
doctors now believe may increase chances of developing the disease. The
therapy used high doses of vitamin E to keep the coronary arteries healthy,
treatment that was later shown to be ineffective in randomized trials.
In spite of the conflicting research, Nutritional Epidemiologist Eric Rimm
standing by his work. Rimm's study showed vitamin E reduced the risk of
developing coronary-artery disease in healthy men ages 40 to 75. "I think
originally reported hasn't really been re-tested," he said. The follow-up
cited by Ioannidis tested whether vitamin E prevented heart attacks and
in men and women over the age of 55 who already had cardiovascular disease
diabetes. According to Rimm, the health benefits of antioxidants like
provide is still a lively debate. "I thought our findings would be more
generalizable," Rimm said, "But I think our results stand up, it just
protect people with existing heart disease."
Over generalizing research results is one way that Ioannidis sees medical
being misused by doctors. "There are many issues that are not finalized with
single study," he said, "issues like trade-offs between benefits and harms,
side-effects, and generalizability." If Ioannidis' work can be said to have
moral it is - don't put too much faith in one study.
Solving the problem is not as simple as sticking to randomized experiments
requiring results to be duplicated. Observational studies, like Rimm's
research, are not randomized, but they can provide a foundation for future
research. Likewise, duplicating research results can be unethical, and that
be the case for the 11 studies in his survey that have not been followed-up.
case is a clinical trial of the drug Zidovudine, a medication that was 75
effective in preventing HIV positive mothers from transmitting the disease
their unborn children. Re-testing Zidovudine would require exposing some
children to an increased risk of HIV infection. So, how should patients deal
"We should switch our mode of thinking about a statistically significant
to what I would call a credible result," said Ioannidis. He proposes a
rating published research based on the rigor of its experimental design,
size and amount of supporting research. "There is nothing wrong about
acknowledging that all of the research published in medical journals is not
one-hundred percent credible," he said. "There is no perfect research."
Ioannidis advises patients to protect themselves by taking a more critical
approach to their doctor's advice. "Ask not just 'is it good for me?' but
is the uncertainty?"- Zach Zorich
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