[Paleopsych] Discover: A third of medical research wrong?

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A third of medical research wrong?
http://www.discover.com/web-exclusives/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 
medical
    studies by epidemiologist John Ioannidis found the results of 14 studies 
were
    contradicted or downplayed by later research.  Ioannidis' survey raises some 
hard
    questions.  Is there a fundamental flaw in medical research, or is this just 
part
    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 
cases
    of preventive therapies for coronary-artery disease.  One study recommended
    hormone replacement therapy for post-menopausal women -- a treatment that 
some
    doctors now believe may increase chances of developing the disease.  The 
other
    therapy used high doses of vitamin E to keep the coronary arteries healthy, 
a
    treatment that was later shown to be ineffective in randomized trials.

    In spite of the conflicting research, Nutritional Epidemiologist Eric Rimm 
is
    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 
what we
    originally reported hasn't really been re-tested," he said.  The follow-up 
study
    cited by Ioannidis tested whether vitamin E prevented heart attacks and 
strokes
    in men and women over the age of 55 who already had cardiovascular disease 
or
    diabetes. According to Rimm, the health benefits of antioxidants like 
vitamin E
    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 
doesn't
    protect people with existing heart disease."

    Over generalizing research results is one way that Ioannidis sees medical 
studies
    being misused by doctors. "There are many issues that are not finalized with 
a
    single study," he said, "issues like trade-offs between benefits and harms,
    side-effects, and generalizability." If Ioannidis' work can be said to have 
a
    moral it is - don't put too much faith in one study.

    Solving the problem is not as simple as sticking to randomized experiments 
or
    requiring results to be duplicated.  Observational studies, like Rimm's 
vitamin E
    research, are not randomized, but they can provide a foundation for future
    research.  Likewise, duplicating research results can be unethical, and that 
may
    be the case for the 11 studies in his survey that have not been followed-up. 
One
    case is a clinical trial of the drug Zidovudine, a medication that was 75 
percent
    effective in preventing HIV positive mothers from transmitting the disease 
to
    their unborn children.  Re-testing Zidovudine would require exposing some 
unborn
    children to an increased risk of HIV infection. So, how should patients deal 
with
    the confusion?

    "We should switch our mode of thinking about a statistically significant 
result
    to what I would call a credible result," said Ioannidis.  He proposes a 
system of
    rating published research based on the rigor of its experimental design, 
sample
    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 
'what
    is the uncertainty?"- Zach Zorich