An recent article in the journal Ophthalmology reported the results of a clinical trial that evaluated acupuncture as an adjunctive treatment for anisometropic amblyopia. In the abstract, the authors conclude:
Acupuncture is a potentially useful complementary treatment modality that may provide sustainable adjunctive effect to refractive correction for anisometropic amblyopia in young children. Further large-scale studies seem warranted.
A little background information is in order.
In a healthy visual system the various structures in the eye focus light ambient light to form a sharp image on the retina. The retina functions like the CCD in a digital camera. Light energy is transduced to electrical signals, which are transmitted through the optic nerve. The signals from the optic nerve are relayed to the occipital cortex (at the very back of the brain) where they are interpreted into the experience of vision.
Amblyopia is often called “lazy eye”. If during childhood the brain is deprived of quality visual information it does not mature properly and loses the potential for good vision. Any opacity within the eye which significantly degrades the quality of the image forming on the retina (such as congenital cataract) can cause amblyopia. Strabismus (misalignment of the 2 eyes) can also cause amblyopia. If the eyes are not aligned, the brain has difficulty reconciling the disparate images from the 2 eyes. In order to avoid double vision the brain may “ignore” the input from one eye, and corresponding part of the visual cortex will not develop properly. Extreme, uncorrected, refractive errors (nearsightedness, farsightedness or astigmatism) can cause amblyopia. Patients with different refractive errors in their 2 eyes, a condition known as anisometropia, can also develop amblyopia in one eye.
Multivitamin supplementation has been getting a rough ride in the literature, as evidence emerges that routine supplementation for most is, at best, unnecessary. Some individual vitamins are earning their own unattractive risk/benefit profiles: Products like folic acid, calcium, and beta-carotene all seem inadvisable for routine supplementation in the absence of deficiency or medical indication. Vitamin E, already on the watch list, looks increasingly problematic, with data recently published confirming the suspected association of supplementation with an elevated risk of prostate cancer.
Reading through the vitamin posts here at SBM, one issue comes through repeatedly: The danger of assuming therapeutic benefits in the absence of confirmatory evidence. Vitamin supplement have the patina of safety and of health, a feature that’s reinforced when you purchase them: You don’t need a prescription, you don’t get counseled on their use, and there isn’t a long list of frightening potential side effects to accompany the product. You can pull a bottle off the shelf, and take any dose you want. After all, how harmful can vitamins be when you can buy 5 pounds of vitamin C at a time, or vitamin E capsules in a 1000-pack? But the research signals seem to be getting stronger, and most are pointing in the same direction: what we though we knew about antioxidants was based on simplistic hypotheses about nutrition and health. And while we thought we were doing ourselves good with antioxidant supplements, we may have been doing harm. (more…)
Prince Charles is a big supporter of “natural” medicine, which in practice means unscientific and ineffective medicine. He has no particular expertise in this area, and there is absolutely no legitimate reason why he should have any influence over the practice of medicine in the UK. But he is the Prince of Wales, and he has chosen to use that celebrity to promote CAM.
Prince Charles has also recently been criticized for his credulous support for medical nonsense. The Telegraph recently reported that Simon Singh, co-author with Edzard Ernst of Trick or Treatment, and exposer of CAM pseudoscience, spoke about Prince Charles at the recent Hay Festival in India. Singh had some sharp criticism, including:
He only wants scientific evidence if it backs up his view of the natural treatment of health conditions…
We presented evidence that disputes the value of alternative medicine and despite this he hasn’t changed his mind…
Every so often, I come across studies that leave me scratching my head. Sometimes, these studies are legitimate scientific studies that have huge flaws or come from an assumption that is very off-base. Other times, they involve what Harriet Hall has termed “tooth fairy science,” wherein the tools of science are used to study a phenomenon that is fantastical, whose very existence hasn’t been demonstrated. Many such studies, not surprisingly, are studies of “complementary and alternative medicine” (CAM) or “integrative medicine” (IM). Modalities like reiki (which is faith healing that substitutes Eastern mysticism for Christian beliefs) and homeopathy (which is, when you boil it down to its essence, sympathetic magic) fall into the category of therapeutic modalities that are based on fantasy but are studied as with the latest tools of science, producing no end to confusing noise. This “tooth fairy science” has, over the last few years, reached its epitome in the application of the latest genomics technology to, in essence, magic, and I’ve recently come across an incredible example of just such a thing. But, first, let’s take a step back to what is going on in medical science now before I introduce a concept that I’ve dubbed “woo-omics.”
A prelude to woo-omics: Genomics, proteomics, everywhere an “omics”
One of the most difficult problems in science-based medicine is how to do a better job identifying which patients will respond to which treatments. Clinical trials, by their very design, have to look at average responses in populations. In essence, a treatment is compared to either placebo or standard-of-care, a choice mainly driven by ethics and whether effective treatments exist for the condition being studied. It is then determined using statistics whether a significant difference exists between the two groups. The difficulty, as any clinician knows, is applying the results of clinical trials to individual patients. In any population, there is, after all, a range of responses to any drug or treatment, and it would be desirable to be able to predict which patients will fall at the end of the bell-shaped curve where the treatment is most effective and which will fall at the end of the curve where the treatment works poorly or not at all.
There have not been a lot of topics of late that warrant extensive analysis and discussion. But there are a number of little topics of interest, each worthy of a few paragraphs of discussion, archetypes of issues in medicine, science based and otherwise.
Xigirs. No, it is not whale vomit, but close.
Last month Xigris was pulled from the market by Lilly. Yes, I understand the shock. Xigris, we hardly knew ye. Xigris is the brand name for drotrecogin alfa, or activated protein C. It is an enzyme in the clotting cascade that is/was given for the treatment of sepsis. (more…)
Oh no! Not again! The venerable medical journal Pediatrics devotes an entire supplement this month to Pediatric Use of Complementary and Alternative Medicine: Legal, Ethical, and Clinical Issues in Decision-Making.
We sense from the very first sentence that we are in familiar territory:
Rapid increases the use of complementary and alternative medicine (CAM) raise important legal, ethical, clinical, and policy issues. (S150)
“Rapid increases”? And evidence of these “rapid increases?” None cited.
We do, however, see the same shopworn reference to popularity deconstructed elsewhere on SBM. What we learned by actually examining “the large 2007 US survey” which purportedly “revealed that ~4 in 10 adults and 1 in 9 children and youth used CAM products or therapies within the previous year”(S150) is that
…most hard-core CAM modalities are used by a very small percentage of the population. Most are less than five percent. Only massage and manipulation are greater than 10 percent. These numbers are also not significantly different from 10 or 20 years ago — belying the claim that CAM use is increasing.
We also find this definition of “CAM”:
a broad domain of healing resources …other than those intrinsic to the politically dominant health system of a particular society or culture in a given historical period. (S150)
I’m not sure what it takes to become “intrinsic” to the “politically dominant” healthcare system. If it includes being legal, licensed or covered by public and/or private insurance, that would appear to disqualify dietary supplements, chiropractic, acupuncture, homeopathy, homeopathic products and naturopathy as “CAM” in some, or in some cases all, of the American states.
I just returned from a trip to Montreal where I spoke at the Lorne Trottier Public Science Symposium, an annual event that David Gorski spoke at a year ago. My topic was “Puncturing the Acupuncture Myth” and the other speakers were Paul Offit, Edzard Ernst, and Bob Park. I was honored to be in such august company; and we were wined, dined, and cossetted: overall, an experience that will count among the high points of my career. In addition to speaking at the Symposium, I was interviewed on the radio; participated in a roundtable discussion with other doctors, scientists and journalists; and was invited to speak to a large freshman chemistry class at McGill University. I told the students a bit about how I came to be the SkepDoc and some of the things I’ve written about, with “Vitamin O” as an example, and I provided 3 “lessons I have learned” from my investigations that are general principles applicable to other fields:
- Roosters don’t make the sun come up.
- Never believe one study.
- The SkepDoc’s Rule of Thumb: when encountering a new or questionable claim, always try to find out who disagrees and why.
My presentation was recorded and is available as a webcast. Scroll down to “2011/11/08 HallOffit” near the bottom and click on the appropriate symbol to the far right. That saves me having to write a post this week. I think SBM readers will find it pertinent to all we discuss here.
A Loose End
In the last post I wondered if Ted Kaptchuk, when he wrote the article titled “Effect of interpretive bias on clinical research,” had understood this implication of Bayes’s Theorem: that interpretations of most scientific investigations are exercises in inverse probability, and thus cannot logically be done without consideration of knowledge external to the investigation in question. I argued that if Kaptchuk had
…understood the point when he wrote his treatise, he was dishonest in not explaining it and in not citing at least one pertinent article, such as Steven Goodman’s (which I’m willing to bet he had read). If he didn’t understand the point he should have withheld his paper.
In researching more of Kaptchuk’s opinions I’ve discovered that he had certainly read Goodman’s article, but that he either didn’t understand it or preferred to obscure its implications in deference to his ongoing project in belittling scientific knowledge. In a letter to the editor of the Annals of Internal Medicine in 2001, Kaptchuk opined that even if “more trials of distant healing with increased methodologic rigor” were positive, it still would not “be persuasive for the medical community”:
The situation resembles the predicament with homeopathy trials, another seemingly implausible intervention, where the evidence of multiple positive randomized, controlled trials will not convince the medical community of its validity. Additional positive trials of distant healing are only likely to further expose the fact that the underpinning of modern medicine is an unstable balance between British empiricism (in the tradition of Hume) and continental rationalism (in the tradition of Kant).
…It seems that the decision concerning acceptance of evidence (either in medicine or religion) ultimately reflects the beliefs of the person that exist before all arguments and observation. [Kaptchuk cites the second of the two Goodman articles that I referred to above, discussed here]
Scientific medicine is not easy. By this point we have largely picked the low hanging fruit, and continued improvements are mostly incremental and hard won. In order to get the most out of our limited research dollars, and optimize medical practice with the safest and most effective treatments, we need to use all available scientific evidence in the proper way. That is the essence of SBM.
There are those, however, that misuse or abuse the scientific evidence — whether to promote an ideology, out of innocent ignorance, or for nefarious purposes. In order to be truly science-based a medical intervention should be plausible, or at least not implausible, based upon basic science evidence, and it should actually be safe and effective when tested in people. Therefore, medical practices can fail to be scientific for one of two broad reasons: they can be scientifically implausible, or they can lack proper clinical evidence for safety and efficacy (or even have evidence for lack of efficacy). Some modalities (like homeopathy) fail on both counts.
The more pernicious medical claims are those that seem highly plausible, that can be extrapolated from basic science, but simply lack adequate clinical evidence. Stem cell clinics are an example — they can easily dazzle desperate patients with scientific descriptions of how stem cells work, and even cite published basic-science papers showing the potential of this technology. But what they cannot do is provide clinical evidence that the specific intervention they are offering is safe and effective for the specific disease or condition they are treating.
I normally write the first draft of this blog the weekend before it is due, and this is no exception. However, I am ill this weekend. Headache, myalgias., painful cough, but only mildly ill. The worst part is the interferon induced brain fog; my thoughts flow with all the speed of pudding and I was not appreciably better as the week progressed, although no cracks about how you can’t any difference in my writing over baseline.
I doubt the cause of my symptoms is influenza. According to the CDC site and Google flu trends there is little influenza activity in the US at the moment, so it is probably one of the innumerable viruses that can cause a flu-like illness. I am also not ill enough to think I have influenza, but I could be having a modified course as I was vaccinated a month ago. Of course, the doctor who treats herself has a fool for a patient and an idiot for a doctor. Flu season approaches, so from my interferon addled brains, flu thoughts.