Sunday, April 04, 2010
Evidence-Based Medicine? (Part 3)
By Christopher Johnson, ND
Lack of evidence in conventional medicine
“The weakness of the scientific evidence underlying medical practice is one of the causes of the wide variations that are well recognized in medical practice”
- Richard Smith, Former Editor BMJ
In the previous 2 segments of this series on evidence-based medicine, I demonstrated how research funded by medical industries (primarily the pharmaceutical industry) is systematically biased and corrupt and how that information is then disseminated to doctors and the public through medical journals and the mainstream media. The result of this situation is that much of the evidence upon which the practice of medicine is based is unreliable.
In this section I will show that apart from the problem of data being unreliable, much of medical practice is not based on any data at all.
The journal Clinical Evidence is a BMJ-owned journal dedicated to assessing the evidence base of medical therapies. It is run by a group of veteran medical journal editors and has conducted the most thorough evaluation to date of this issue, utilizing the expert judgment of medical experts and researchers from across the globe. Over 500 peer reviewers and 500 authors regularly contribute to this effort. No other group comes anywhere to close to this degree of thoroughness and breadth in examining the available data.
So far the group has reviewed the evidence base of 2,500 medical treatments. It found that 49% of these medical therapies have no evidence of either efficacy or safety. Another 8% of therapies have solid evidence of either being harmful or not likely to be beneficial. And an additional 8% have trade offs between harms and benefits.
That leaves only 35% of medical therapies which have evidence of being either beneficial or likely to be beneficial. Of this fraction, only 12% are known to be beneficial; the other 23% ‘likely to be beneficial’.
Of this 35%, how much of the evidence is actually fraudulent, fabricated, or otherwise misleading? (as we know occurs regularly with industry-funded research) Even veteran medical journal editors and professionals have no way of knowing if findings were falsified – they have to take the numbers at face value.
And how much evidence of treatments being harmful was withheld by drug companies and never published? (again, a common practice which has been well-documented)
Considering these questions, the numbers are likely to be even worse – with less evidence of benefit and more evidence of harm.
David Eddy is a professor of health policy and management at Duke University. He began his career as a cardiothoracic surgeon at Stanford but became concerned with what he saw as a lack of evidence base in medical practices. To explore this idea he chose a specific condition – glaucoma – and set about combing the medical literature for evidence of the procedures and medications used to treat it. He reviewed the entire body of medical literature concerning glaucoma all the way back to 1906 and could not find a single randomized controlled trial which investigated the standard treatments. Yet there were numerous mentions in medical journals and textbooks about the efficacy of the treatments – all based on hearsay and speculation.
Professor Eddy now advises medical ‘consensus’ groups. Consensus groups are panels of experts in a given condition who work to come up with advice for doctors in treating the condition. One such panel of which Dr. Eddy was actually a member looked at colorectal cancer screening. The international group met several days a year for several years, and subsequently issued a set of guidelines on the matter. When he privately asked the other members of the group their opinion on how much the recommendations would reduce incidence of colorectal cancer the answers ranged from 0 to 100%. Yet there was supposedly “consensus”.
A 1991 BMJ article had the following to report concerning Dr. Eddy’s dealings with these consensus groups: “For 21 problems tackled so far the evidence has been judged – by the experts – to be between poor and none for 17, and usually the best available evidence was something less than a randomized controlled trial. Often the evidence that was available contradicted current practice.”
In the next segment, I will continue to demonstrate with specific examples, how the supposed edifice of ‘evidence based medicine” is not all it is cracked up to be.
Christopher Johnson, ND is a naturopathic doctor specializing in the use of homeopathy and nutrition to address a broad range of conditions in both the adult and pediatric populations. He is owner of Thrive Naturopathic, a holistic health care facility located in Alexandria, Virginia. He speaks widely on how homeopathy is the answer to many of today's health challenges, and is available for phone consultations for those not in the area. Visit his website at: www.ThriveNaturopathic.com