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Who Says Skeptics Aren’t Fun?
A 9-minute beat poem of rationalism and skepticism. Who says skeptics aren’t funny?! 🙂
Posted in Humor
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The End of Chiropractic? Of Course Not.
At last, the definitive nail in the coffin of chiropractic? Hardly. A recent study in the journal Chiropractic and Osteopathy uses an epidemiological approach to examine the question of whether the founding “lesion” of the chiropractic philosophy, the vertebral subluxation, can be shown to be associated with any disease. Their conclusion reads like a Science-Based Medicine or Quackwatch summary:
“Subluxation was not found to be linked to any one disease complex…There were no studies that offered a biological plausibility that would isolate subluxation as a causal factor in disease. There were no studies linking the subluxation as a coherent construct and supported by generally known facts about the natural history and biology of any disease. There were no studies found that suggested the subluxation as a causal agent similar to other factually demonstrated causal agents…There is significant lack of evidence to fulfill basic criteria of causation. This lack of crucial supportive epidemiologic evidence prohibits the accurate promulgation of the chiropractic subluxation.”
Short and sweet, the basic abnormality chiropractors claim to fix cannot be shown to exist or to cause any disease. One might think this would be a fatal blow to the enterprise of chiropractic, but sadly that is not the case. For one thing, it has been shown before in other studies that the subluxation cannot be reliably identified by chiropractors and that when pushed to demonstrate it in some objective way, most chiropractors and their lobbying organizations engage in some impressive yoga to cover the fact that they cannot. But as chiropractic is fundamentally faith-based medicine, being unable to demonstrate that the disease they are treating exists doesn’t worry chiropractors. Even those who disavow the subluxation theory happily continue the sort of manipulative practices Palmer originally invented to fix the supposed subluxation, and they simply justify it with the time-honored refuge of all woo, “Well, I don’t know how or why it works, but it works!”
Of course, this conclusion cannot be reliably demonstrated by objective evidence either. Though chiropractic does seem to have some benefit on subjective perceptions idiopathic lower back pain, the fact is it has been shown to be at best roughly equivalent to conventional therapy (rest, NSAIDs, physical therapy, and patient education materials) or to a good massage. If it were truly risk free and presented truthfully as offering mild benefits for back pain, I would have no objections. And a few chiropractors have adopted this approach in an attempt to take what benefit their interventions might provide out of the realm of faith and into that of responsible medicine, but these are a minority and often reviled within their own profession. But while I believe evidence is critical and should be the cornerstone of medical practice, I also understand that it is not as compelling as personal experience for many people, and the first step on the road to recovery from addiction to unscientific therapies is to understand we have a problem and need something better than our own experience and intuition to validate or invalidate the safety and efficacy of medicine. So while this should be a critical study undermining the claims of mainstream chiropractic, it has garnered little attention and will probably have little impact on the popularity of the method.
Posted in Chiropractic
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Benefits & Risks of Neutering–What does the science say?
Many pet owners have questions about neutering their pet dogs and cats, and while there is much useful information available on the Internet, there is also much misinformation. I have composed a literature review looking at the benefits and risks of spaying and neutering. It is too large to post directly here, so I have uploaded it as a .pdf file on SkeptVet.com. I hope also to soon have a simplified, tabular version for those disinclined to wade through the detailed consideration of all the pros and cons.
Posted in Science-Based Veterinary Medicine
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Homeopathy Works for Arthritis–Or Maybe Not
I recently ran across an article in the journal Evidence-Based Complementary and Alternative Medicine (eCAM) titled Evaluating Complementary Therapies for Canine Osteoarthritis–Part II: A homeopathic Combination Preparation (Zeel) (Hielm-Bjorkman, A et al 2009:6(4)465-471).
According to the authors, “a homeopathic combination product (HCP) for canine osteoarthritic pain was evaluated in a randomized, double-controlled and double-blinded clinical trial…[and] that the HCP (Zeel) was beneficial in alleviating chronic orthopedic pain in dogs, although it was not as effective as Carprofen.”
There are many levels on which any clinical research article should be critically evaluated. The potential biases of the authors and the journal, the quality of the methodology, the statistical analysis of the data, and the degree to which the conclusions follow from the data are all common criteria by which such publications can be judged. R. Barker Bausell in his book Snake Oil Science does an outstanding job illustrating some reasons why not everything that makes its way into a scientific journal is reliable science and why such critical evaluation is necessary.
In this case, the journal makes some effort to follow the principles of evidence-based medicine, but it is guilty of some serious Tooth Fairy Science, in which rigorous methodology is applied to some fundamentally irrational premises. Skimming through some archival issues also indicates a pretty strong preference for publishing positive findings for CAM interventions. None of this automatically invalidates anything published, but it is one factor to consider since the effect of personal as well as financial biases on research outcomes is well established.
As for the authors, I am not able to establish much about their biases. Two of the authors are professors at the University of Helsinki School of Veterinary Medicine, and the lead author’s research summary  suggests a strong attachment to CAM. Her doctoral dissertation was a study on gold implantation, green-lipped mussel extract, and Zeel for use in canine osteoarthritis, and it appears she is publishing this thesis research as a series of articles in eCAM.
The methodology is generally sound, with a couple of exceptions. First, while the product studied is identified as homeopathic and an inject able version of it is listed in the US Homeopathic Pharmacopoeia, even the authors insert the caveat that “this is not a classical homeopathic treatment.” The preparation contains 14 listed ingredients, many of which are present after having been diluted 1:10 only 2-8 times, for “molar concentrations of 10-5 to 10-12mol/L.” Such concentrations are low, but still higher than the usual case for homeopathic preparations, which cannot conceivable contain any of the original ingredient. It is possible, then, that this substance could contain some pharmacologically active substances. The ingredients listed (same as the injectable product) are:
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- Arnica montana, radix (mountain arnica)
Dulcamara (bittersweet)
Rhus toxicodendron (poison oak)
Sanguinaria canadensis (blood root)
Symphytum officinale (comfrey) - Mineral ingredients:
Sulphur (sulphur)
(alpha)-Lipoicum acid (thioctic acid)
Coenzyme A (coenzyme A)
Nadidum (nicotinamide adenine dinucleotide)
Natrum oxalaceticum (sodium oxalacetate)Â Â Â - Animal-derived ingredients
Cartilago suis (porcine cartilage)
Embryo totalis suis (porcine embryo)
Funiculus umbilicalis suis (porcine umbilical cord)
Placenta suis (porcine placenta)
The subjects were appropriately randomized into treatment, placebo, and positive control groups, with Carprofen as the positive control. The subjects in each group all appear to be comparable at baseline. The placebo group did have higher baseline scores on 5/7 measures of pain, but the authors state that no statistically significant differences were found between groups at this point.
The placebo control was not ideal. The treatment product was visibly different from the Carprofen and the placebo (which were identical to each other). The owners were given extra Carprofen in its original packaging for rescue, so clearly they would be able to identify the treatment product as different. In addition, all subjects also received an inert capsule as part of a separate study, so while the Zeel group received “an ampoule of clear liquid” once daily and “a slightly green (lactose) capsule,” the Carprofen and placebo groups received the green capsule and “a white pill” twice daily. It is not clear what if any affect such a discrepancy might have had on the subjective assessments of owners, or potentially blinded investigators who might have detected group assignment from comments made by owners.
Most of the assessment measures were subjective, such as owner rating scales or visual analog pain scores and investigator clinical exam assessment. Some force plate analysis was done, though this proved problematic. Two subjects had to have their force plate measurements discarded because they were too lame to allow accurate measurement. These subjects, however, were all in the placebo arm and so this would be expected to have the effect of decreasing perceived efficacy of the treatment.
The force plate measurements were “repeated until sufficient valid results were obtained for both left and right limbs.” It was not stated whether the number of trials needed to achieve this differed between groups, which could have affected the results is some subjects had to run back and forth significant more than others to get a valid reading, which might itself affect the reading.
The biggest methodological problem I see in the study is in order to calculate the percent of subjects improved or not improved in each group at the 8-week assessment period, “the results of each variable were converted into dichotomous responses of ‘improved’ or ‘not improved.'” Converting scale variables into dichotomous variables can exaggerate differences between groups. If the measurement was unchanged, the subject would be classified as “not improved,” but if there was even a miniscule change from baseline then the subject would fall into either “improved” or not “improved category.” Thus, subjects with dramatic improvements in scale measurements would be weighted the same as subjects with marginal, and likely clinically insignificant changes in the variable. Without the raw data, of course, it is impossible to tell what if any effect this procedure might have had on the final conclusions. However, the tabulation of the data presented in the article appears to show much greater improvement in terms of the percentage of subjects improved than in terms of the actual median improvement of the variables themselves, suggesting that in fact such an exaggeration occurred.
The authors also stated that “for dogs that had used extra Carprofen more than three times per week at W8 [4 dogs in the placebo arm] we changed all their variable values at evaluation W8 into the most negative value measured at that time.…to counteract the effect of the NSAID…” This seems a clear fudging of the data which made the placebo group appear to have worse outcome measures than it actually did. Certainly, it is possible that these dogs needed more Carprofen than the treatment group because the treatment was having a beneficial effect. But it is just as possible that the placebo group took more Carprofen because of differences in disease severity, in owner attitudes or behavior, or some other factor. And what makes the arbitrary designation of three times a week an appropriate justification for altering the data in this way is unclear. In any case, the effect of this decision is to make the outcomes appear worse for the placebo group, which clearly makes the treatment group outcomes appear relatively better.
Patients given Carprofen clearly showed improvement over baseline at a rate significantly higher than placebo. 67-86% of subjects were categorized as “improved” for the various outcome measures, and the actual values for each measure were improved from 2-5 times more than for the Zeel group. In the treatment group significantly more subjects were classed as “improved” compared to placebo in 3 out of 6 measures. Again, this is likely inflated by the conversion of scale data to dichotomous data. The Zeel group also showed significantly greater improvement than the placebo group in 4 out of 6 specific measures, though for one the P value was 0.049, quite close to the cutoff of 0.05. Â
The authors also state that use of supplemental or rescue Carprofen occurred in 14% of the Carprofen group, 28% of the Zeel group, and 8% of the placebo group. Though they claim that the only significant difference was between the Carprofen and placebo groups, this is puzzling, both because the Zeel group had a percent of rescue use dramatically higher than the other groups, and because of the earlier statement about manipulating the data for the placebo group to “counteract” the effect of Carprofen use for that group.
No differences in bloodwork values or clinical side effects were seen between groups.
The authors also make the unsupported statement that “it is generally accepted that seasonal differences influence OA, with patients being worse in cold, damp and unstable weather.” A number of studies have found this traditionally assumed relationship to be difficult to verify and likely a minor and insignificant factor in arthritis pain for most patients (1, 2, 3), so it does not qualify as “generally accepted.” Nevertheless, the authors go on to claim that a trend observed of worsening symptoms for the placebo group during the treatment phase of the study and subsequent improvement during the post-treatment follow-up was due to the weather, and that the opposite trend seen in the Zeel and Carprofen groups was due to the effects of the treatment agents. It seems more likely that the placebo group simply different in significant ways from the other groups, which casts further doubt on the conclusion that the test product was of meaningful benefit.
The authors conclude by putting the usual best possible spin on the weak results, suggesting that combined with in vitro results reported elsewhere they justify further research and pointing out that NSAIDS, which even they acknowledge are clearly superior for treatment of pain, have side effects, despite the fact that none were seen in this study. As I’ve said before, the resource limitations on research in veterinary medicine requires the most efficient use of those resources to maximize benefit, and such studies of implausible interventions are not going to benefit our patients. The authors clearly wish to find something positive in their results, but the study does not justify the commitment of more time and resources and talent to this methodology when better therapies are already available, and when decades of research on homeopathic preparations has failed to validate them. Such papers provide the aura of scientific legitimacy to such methods, but they are tooth fairy science, not evidence-based medicine, and they are a dead end we would do well to stop travelling down.
Posted in Homeopathy
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Internet Information — The Good, Bad, and Ugly
As we all know, the Internet is a mixed blessing. It makes enormous amounts of information easily and cheaply available to billions of people. Unfortunately, not all information is created equal, and sometimes bad information is worse than none. Contrary to what many of my clients assume, I actually appreciate it when they come to me with questions or suggestions based on their own research. However, when they have been misled by unreliable sources, a great deal of their enthusiasm and effort ends up being wasted.
I am hoping to contribute eventually to a more comprehensive set of evidence-based veterinary medicine resources under the auspices of the EBVMA, but in the meantime I have assembled some general guidelines and specific sources to trust, as well as some to avoid. I hope this is helpful.
General Principles for Evaluating Internet Information
1. Consider the Source: We need EBM precisely because even the most intelligent and honest of us cannot avoid the influence of bias on our conclusions. The universal cognitive biases and perceptual biases we all share, as well as the more obvious errors associated with strong feelings and preconceptions make a truly objective evaluation of any complex phenomenon impossible. The scientific method compensates for such sources of bias imperfectly, but better than anything else yet discovered.
When evaluating information from the Internet, it is important to consider the possible sources of bias lurking behind it. These biases do not automatically invalidate the information by any means, but being aware of them helps inject a salutary element of skepticism about their validity.
Obviously, anyone trying to sell you something is likely to believe quite deeply in what they are selling. Apart from deliberate scam artists, most people don’t enthusiastically promote or make a living selling things they aren’t strongly committed to, so they are unlikely to be truly dispassionate or objective. Confirmation bias is particularly likely to lead people with a financial interest in something to ignore potential problems with it. CAM proponents never tire of making this charge against mainstream medicine, especially the pharmaceutical industry, but they conveniently ignore their own financial interest in the products and services they provide.
Strong ideological positions also call into question the level of fairness in the presentation of an argument. It is so difficult to overcome the influence of one’s deepest held values and philosophies that it is often most useful to simply declare them up front and let those who are trying to puzzle out the truth take them into account. When looking at information provided on the Internet, it is often useful to find sites committed to both sides of an issue and compare the information and arguments.
Sometimes such ideological biases may be hidden, usually in an attempt to prevent people from recognizing them and the influence they may have over the information being provided. However, one advantage to the Internet is that it is often fairly simple to find out a lot about the affiliations and associations of people offering information to the public. My recent post on the association between conservative Catholics and anti-vaccine activists is an example of how hidden agendas behind information presented as objective and scientific can be uncovered.
Finally, while blind reliance on “experts” is a form of faulty reasoning known as the argument from authority, it is still true that specialized training and experience in an area does give somewhat more weight to one’s opinions on the subject. The idea that anyone can be an expert on any subject simply doesn’t hold water in today’s complex and technologically sophisticated world. Personal experience is especially unreliable as a source of deep insights that an entire profession of specialists have missed. A few hours on the Internet can’t make me into a nuclear physicist, and it can’t make a physicist into a veterinarian. So while no one is automatically right just because they are a specialist or professional in a subject, it is unlikely that dilettantes and self-made experts are going to have insights or wisdom that such professionals lack.
2. Check References: In CAVM it is very common to cite scientific sources in support of mistaken arguments. It is also often the case that when one reads the original source, it doesn’t say what the person citing it claims it says. Taking information or quotations out of context, overlooking obvious flaws in methods or argument, and simply cherry-picking sources that say what you want them to while ignoring those that don’t are all practices that make such research citations unreliable. So whenever possible, check the original source to see if it really does support the argument you’re evaluating.
3. Be Reasonable: If it’s too good to be true, it probably isn’t. Extraordinary claims require extraordinary evidence. Pick your cliché, but ultimately reality is complicated and messy and often not how we’d like it to be, so anyone who tells you it is simple and you can have your cake and eat it too is probably deluded or lying.
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Trustworthy Internet Resources
These are resources that I believe provide information that is reliable. Being run by human beings, they may not always be right, but they are not regularly, egregiously wrong or out to push a product. Some may have obvious biases in favor of science and methodological naturalism, but if one rejects these positions then one has already decided rational and objective inquiry is impossible or undesirable anyway, so trying to evaluate the rationality and objectivity of Internet information isn’t likely to be a concern. Postmodernists and those who see faith and revelation as the keys to truth aren’t likely to find any of this useful anyway.
Many of these resources address human medicine primarily, and many include subjects outside of medicine all together. There is an unfortunate paucity of good resources for science-based veterinary medical information on the Internet, though obviously I am trying to change that! however, despite the dangers of extrapolation across species, the information gathered in human medicine can be used to assist our judgments regarding veterinary medical questions.
The SkeptVet- Though this blog is the more active part of my Internet project, I have assembled a collection of my more detailed and researched articles and my downloadable client information pamphlets on specific veterinary topics on my main web site. No commercial conflicts of interest, and my ideological biases should be quite obvious.
Evidence-Based Veterinary Medical Association (EBVMA)– This is an organization of veterinarians and other professions, both in academia and private practice, dedicated to promoting evidence-based veterinary medicine. Any veterinarian interested in supporting high quality, science-based veterinary medicine should join and get involved. And a new web site, with practical information and EBM tools for vets is coming soon!
VeterinaryWatch– This site contains a lot of good, science-based information and references, though unfortunately not in a very user-friendly form. I am working with several others to try and improve the design and content of the site, but it is a slow project.
Quackwatch– By far the most extensive collection of resources regarding CAM. Reviews of many products and therapies, warnings about corporate and individual providers or CAM services and information, and links to many other reliable resources.
Science-Based Medicine– Far and away the best blog on science and evidence-based medicine and a great resource on CAM. Intelligent, thoughtful, and well researched essays on a large variety of topical as well as perennial issues.
The Cochrane Collaboration– The premier site for EBM in the human medical field. Though some resources are available only on a subscription basis, the most helpful resource are summaries of the independent and rigorous systematic literature reviews on a large number of specific topics.
PubMed– An enormous and easy to use database of the medical literature. Abstracts are available for most articles, and links to sources for the full text. Unfortunately, full text access for many articles is available only to subscribers of the publishing journal, but the world of medical publishing is changing, albeit slowly, and more journals become accessible all the time.
Free Medical Journals– A convenient way to identify journals that offer free online access to their content. While many of the highest impact journals in human medicine are open access, far fewer veterinary journals are available–yet.
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Unreliable Internet Resources
While the number of commercial organizations and individuals pushing misleading information or outright nonsense on the internet is vast beyond imaging, this is a list of some of the more popular, and hence more dangerous. And while the distinction between bad science, pseudoscience, and plain quackery can sometimes be a tough call, a place to start for the more egregious cases is The Quackometer. This automated tool evaluates websites for language patterns typical of pseudoscience and medical quackery. Of course, I would never suggest letting a machine make your decisions for you, but I’m surprised by how often I agree with the little black duck!
Shirley’s Wellness Cafe– This is perhaps the most egregious woo site I’ve found to date. Vicious and paranoid condemnation of all scientific medicine as paternalistic, venal, and harmful. Wild claims about safe, natural, free cures for almost everything. No logic or data, only the presumption that if it is in any way scientific it must be bad for you. And despite the railing against the greedy medical establishment, there sure seem to be a lot of things for sale!
Healthy Pet Journal– A sad example of veterinarians giving up on science in favor of blind faith and intuition. The site doesn’t have the hysterical shrieking tone of Shirley’s, but that makes it even more dangerous since the information is presented as if it were reasonable and scientific, when it almost universally is neither.
Naturallycomplementary.com– A beautiful, well-organized, easy to use resource for avoiding science-based medicine and finding all things CAVM. A huge variety of unrelated and mutually contradictory approaches are promoted, with the only apparent unifying feature being claims of “natural,” “alternative,” “holistic” and so on. Words which have lost whatever meaning they may once have had and have become merely shibboleths for anti- and pseudoscience. I tried to register as a member of the forum to offer a different perspective, but apparently the management is not interested in allowing members to hear other points of view, and they denied my application.
Academy of Veterinary Homeopathy– A professional organization of veterinarians devoted to this tooth fairy science.* (sigh)
American Holistic Veterinary Medical Association– Ditto. This one is good for some laughs if you check out the offerings at their annual CE meeting.
Sadly, I could go on endlessly. While thankfully science-based medicine is far more widely available and accepted than CAVM, promoting CAVM on the Internet is a viable commercial activity, while promoting EBVM and skepticism is a strictly pro bono volunteer task. Consequently, the volume and shiny façade of the CAVM offerings will always outshout and outshine the more rational alternatives. But once you examine a few examples of unreliable sources, the patterns of language and argument become obvious, and your internal quackometer should steer you straight.
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*”This study falls into the category of what I call Tooth Fairy science. You could measure how much money the Tooth Fairy leaves under the pillow, whether she leaves more cash for the first or last tooth, whether the payoff is greater if you leave the tooth in a plastic baggie versus wrapped in Kleenex. You can get all kinds of good data that is reproducible and statistically significant. Yes, you have learned something. But you haven’t learned what you think you’ve learned, because you haven’t bothered to establish whether the Tooth Fairy really exists.” Harriet Hall, MD
Posted in General
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Skeptical Media
Yes, I’ll take the credit for seeing this one first. 🙂 The New York City Skeptics blog Gotham Skeptic has a post about recent pro-science articles appearing in the mainstream media. The post suggests we might finally be emerging from what a friend of mine refers to as the Golden Age of Woo and into a time when skepticism and sound science are again acceptable public positions to support.
They first mention Amy Wallace’s incisive piece in Wired magazine “An Epidemic of Fear: How Panicked Parents Skipping Shots Endangers Us All”, which has been discussed several times over at Science-Based Medicine. They then mention several other examples, including a piece by the Associated Press reporter Marilynn Marchione, whom I previously lauded back in June for her excellent reporting on CAM and pseudoscience. Hmm, I wonder if this might be evidence that I have psychic powers….. 😉
CAM Tries to Cash in on Swine Flu (H1N1) Fears
As I’ve pointed out before, the image of CAM providers as selfless promoters of health without the venal concerns for profit of mainstream medicine and Big Pharma is advertising spin, not reality. A nice example of that has been the recent attempts of many snake oil peddlers to cash in on fears about swine flu (H1N1 Influenza). The Food and Drug Administration (FDA) keeps a list of Fraudulent H1N1 Products. Of course, not all the products are CAM-related, since greed knows no loyalties. However, the majority of the products making unsubstantiated claims about preventing or treating the swine flu make similar claims about disease and health in general, and they include a number of CAM standbys.
Dr. Andrew Weil, a paragon of woo, has received a cease and desist order from the FDA regarding claims, subsequently removed, about his dietary supplement line. The FDA list contains a large number of herbs, vitamins, supplements, and even some teas. Despite the frequent claim that Big Pharma has no interest in these kinds of therapies because they cannot be patented and so there is no money to be made from them, there seem to be a lot of folks making money selling them for many uses, whether they work or not.
Some products are obvious attempts to cash in on flu fears, such as the Flu Away inhaler containing eucalyptus and tea tree oil. Others play more subtly on the fears of H1N1, marketing bogus “information” about the flu along with a broad collection of products and services designed to “promote health.” It is encouraging that the FDA is doing what it can, with limited resources and less public and even government support than it should have, to prevent unscrupulous individuals and companies from making a profit selling useless products and a false sense of security to people with legitimate concerns about the H1N1 pandemic.
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Skeptical Dinosaur Enters the Modern Age
Ok, after much prodding I have set up Facebook and Twitter accounts, so anyone interested in skepticism and veterinary medicine, or for that matter Celtic Folk music, science fiction, or an eclectic array or other inteelectual and aesthetic pursuits should look me up there! 🙂
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123rd Skeptics’ Circle is Live!
Check out the 123rd Skeptics’ Circle. This is a regular blog carnival with posts from all over the world covering topics of interest to skeptics and critical thinkers. This week, you might even see a couple of posts you recognize! 🙂
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