April 19th, 2011 by Harriet Hall, M.D. in Opinion
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Before we had EBM (evidence-based medicine) we had another kind of EBM: experience-based medicine. Mark Crislip has said that the three most dangerous words in medicine are “In my experience.” I agree wholeheartedly. On the other hand, it would be a mistake to discount experience entirely. Dynamite is dangerous too, but when handled with proper safety precautions it can be very useful in mining, road-building, and other endeavors.
When I was in med school, the professor would say “In my experience, drug A works better than drug B.” and we would take careful notes, follow his lead, and prescribe drug A unquestioningly. That is no longer acceptable. Today we ask for controlled studies that objectively compare drug A to drug B. That doesn’t mean the professor’s observations were entirely useless: experience, like anecdotes, can draw attention to things that are worth evaluating with the scientific method.
We don’t always have the pertinent scientific studies needed to make a clinical decision. When there is no hard evidence, a clinician’s experience may be all we have to go on. Knowing that a patient with disease X got better following treatment Y is a step above having no knowledge at all about X or Y. A small step, but arguably better than no step at all.
Experience is valuable in other ways. First, there’s the “been there, done that” phenomenon. Older doctors have seen more: they may recognize a diagnosis that less experienced doctors simply have never encountered. My dermatology professor in med school told us about a patient who had stumped him: she had an unusual dermatitis of her hands that was worst on her thumb and index finger. His father, also a doctor, asked her if she had geraniums at home. She did. She had been plucking off the dead leaves and was reacting to a chemical in the leaves. The older doctor had seen it before; his son hadn’t. Read more »
*This blog post was originally published at Science-Based Medicine*
March 30th, 2011 by Harriet Hall, M.D. in Opinion, Quackery Exposed
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David Kroll’s recent article on thunder god vine is a great example of what can be learned by using science to study plants identified by herbalists as therapeutic. The herbalists’ arsenal can be a rich source of potential knowledge. But Kroll’s article is also a reminder that blindly trusting herbalists’ recommendations for treatment can be risky.
Herbal medicine has always fascinated me. How did early humans determine which plants worked? They had no record-keeping, no scientific methods, only trial and error and word of mouth. How many intrepid investigators poisoned themselves and died in the quest? Imagine yourself in the jungle: which plants would you be willing to try? How would you decide whether to use the leaf or the root? How would you decide whether to chew the raw leaf or brew an infusion? It is truly remarkable that our forbears were able to identify useful natural medicines and pass the knowledge down to us.
It is equally remarkable that modern humans with all the advantages of science are willing to put useless and potentially dangerous plant products into their bodies based on nothing better than prescientific hearsay. Read more »
*This blog post was originally published at Science-Based Medicine*
March 18th, 2011 by Harriet Hall, M.D. in Opinion
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After giving birth, most mammals eat the afterbirth, the placenta. Most humans don’t. Several hypotheses have been suggested as to why placentophagy might have had evolutionary survival value, but are there any actual benefits for modern women? Placentophagy has been recommended for various reasons, from nutritional benefit to preventing postpartum depression to “honoring the placenta.” In other cultures, various rituals surround the placenta including burial and treating it as sacred or as another child with its own spirit. Eating the placenta is promoted by some modern New Age, holistic, and “natural-is-good” cultural beliefs.
Some women eat it raw, but many women have a yuck-factor objection to eating raw bloody tissue. It can be cooked: recipes are available for preparing it in various ways. For those who don’t like the idea of eating the tissue, placenta encapsulation services are available, putting placenta into a capsule that is more esthetically acceptable and that can even be frozen and saved for later use in menopause. Read more »
*This blog post was originally published at Science-Based Medicine*
March 10th, 2011 by Harriet Hall, M.D. in Opinion, Research
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A new article in the Journal of Women’s Health by Westhoff, Jones, and Guiahi asks “Do New Guidelines and Technology Make the Routine Pelvic Examination Obsolete?”
The pelvic exam consists of two main components: The insertion of a speculum to visualize the cervix and the bimanual exam where the practitioner inserts two fingers into the vagina and puts the other hand on the abdomen to palpate the uterus and ovaries. The rationales for a pelvic exam in asymptomatic women boil down to these:
- Screening for chlamydia and gonorrhea
- Evaluation before prescribing hormonal contraceptives
- Screening for cervical cancer
- Early detection of ovarian cancer
None of these are supported by the evidence. Eliminating bimanual exams and limiting speculum exams in asymptomatic patients would reduce costs without reducing health benefits, allowing for better use of resources for services of proven benefit. Pelvic exams are necessary only for symptomatic patients and for follow-up of known abnormalities. Read more »
*This blog post was originally published at Science-Based Medicine*
February 24th, 2011 by Harriet Hall, M.D. in Health Tips, Research
1 Comment »
I was surprised to get this e-mail from a reader:
Surely, Dr. Hall, the public mania for nutritional supplements is baseless. All the alleged nutrients in supplements are contained in the food we eat. And what governmental agency has oversight responsibility regarding the production of these so-call nutritional supplements? Even if one believes that such pills have value, how can the consumer be assured that the product actually contains what the label signifies? I have yet to find a comment on this subject on your otherwise informative website.
My co-bloggers and I have addressed these issues repeatedly.Peter Lipson covered DSHEA (The Diet Supplement Health and Education Act) nicely. It’s all been said before, but perhaps it needs to be said again — and maybe by writing this post I can make it easier for new readers to find the information.
Food, Medicine, or Something In Between?
The FDA regulates foods and has been instrumental in improving the safety of our food supply. It regulates prescription and over-the-counter medications, requiring evidence of effectiveness and safety before marketing. Surveys have shown that most people falsely assume these protections extend to everything on the shelves including diet supplements, but they don’t.
Under the 1994 Diet Supplement Health and Education Act (DSHEA), a variety of products such as vitamins, minerals, herbs and botanicals, amino acids, enzymes, organ tissues, and hormones can evade the usual controls if they are sold as diet supplements. Under the DSHEA, the manufacturer doesn’t have to prove to the FDA that a product is safe and effective; it is up to the FDA to prove that it isn’t safe, and until recently there was no systematic method of reporting adverse effects (required reporting is still limited to serious effects like death).
So far the FDA has only managed to ban one substance, ephedra, and it took the death of a prominent sports figure and considerable skirmishing with the courts to accomplish that. Independent lab tests of diet supplements have found a high rate of contamination (with things like heavy metals and prescription drugs) and dosages wildly varying from the label. A striking example was Gary Null’s recent poisoning with vitamin D from one of his own products which contained 1,000 times the intended amount.
The FDA has issued rules on good manufacturing practices, but standardization is not required and it remains to be seen whether the new rules will effectively improve product quality. Read more »
*This blog post was originally published at Science-Based Medicine*
