Herbalists Apply for Medical Specialty Recognition- An Update

I have been covering the application of the American College of Veterinary Botanical Medicine (ACVBM) for recognition as a specialty in several posts throughout the year (1, 2). My conclusion is that this recognition is not justified for several reasons:

  1. There is very little high-quality or reliable scientific evidence to support the use of herbal products in veterinary patients.
  2. Herbal prescribing is dominated by Chinese Medicine, Ayurveda, and other unscientific folk belief systems, and those proponents who take a more scientific approach are a small minority generally unwilling to reject the claims or methods of alternative herbal medicine.
  3. Herbal products are unregulated, inconsistent and unpredictable in their chemical composition, frequently contaminated with toxins or even undisclosed pharmaceutical drugs, and almost none have been properly tested for safety or efficacy. There is ample evidence of serious harm to human patients from herbal products. The ACVBM supports industry self-regulation rather than the kind of government oversight accepted as necessary for pharmaceutical medicines without any sound reason for doing so.
  4. The majority of the leadership of the ACVBM are dedicated proponents of alternative medicine, not only for herbal products but homeopathy, acupuncture, energy medicine, and many other unproven or pseudoscientific practices. Many have said clear and troubling things that display a contempt for science and science-based medicine and a desire to use the appearance of scientific methods to gain acceptance for alternative practices. This makes it very likely that approval of the ACVBM as a specialty board would serve as a Trojan horse for the legitimization of other alternative therapies.
  5. The potential of herbal medicines would be better explored from a rigorously scientific approach involving specialists in pharmacology, toxicology, nutrition, epidemiology, and other existing medical specialties.

The ACVBM has just released a revised version of their application. While I haven’t exhaustively compared this to previous versions, a couple of sections caught my interest because they directly address some of my concerns and also because they further illustrate the perspective of the group regarding the key issues of science and evidence.

Some material has been added to emphasize why the ACVBM should be a separate specialty college rather than investigating herbal treatments under the auspices of existing specialties.

Veterinary botanical medicine is a distinct discipline that differs in substance, methodology and philosophy from conventional veterinary medicine.

I will briefly comment on some of the specific arguments made to justify this claim.

While many conventional drugs are derived from plants, a veterinarian who prescribes botanical medicine is using whole herbs in preference to isolated active constituents. The whole herb or extracted herb is complex, containing hundreds of constituents that have complex actions…Veterinary herbalists are aware of differences in plant chemistry that may result from the plant’s origins.

The first half of this statement is certainly correct. Whole plants and herbal combinations are chemically very complex. This is usually identified as an advantage (as will be seen below), but it is actually one of the reasons herbal medicine is problematic. The consistency, efficacy, and safety of such complex combinations with variable ratios of different compounds that depend on multiple factors makes it very difficult to accurately predict the effects of such remedies. Herbalists claim to have specialized expertise in doing so, but when investigated these claims amount only to a belief that personal clinical experience or folk medicine traditions are reliable information, which is manifestly untrue more often than not.

That the whole plant is more therapeutic than a constituent is a fundamental principle of botanical medicine supported by research.

Well, the first half of this statement is true as well, but the second half is not. Herbalists believe whole plants to be better than isolated compounds (also known as medicine), but they have in no way proven this through research.  There are studies that show combinations of plant chemicals to be more effective in some uses than each used separately. Most of this is experimental research rather than clinical studies, which is important since the use of such combinations in actual patients is significantly more complex and uncertain.

The idea that combinations of chemicals may have greater effect than the same chemicals used separately is not all that surprising or unique to herbal medicine. Combination regimes of chemotherapy are often more effective than single-drug treatment. And some infections require multiple antibiotics given together to address all the pathogenic organisms involved. However, this does not prove some kind of general principle that combinations are always safer or more effective than single agents. It is equally likely that combinations may have greater toxicity (as if often the case when conventional medicines are used in combination), and sometimes they may interfere with one another. The fact that the compounds occur naturally together in a plant is no reason to imagine we can assume they are better as medicine when given together.

The principle of synergism may turn out to be true in many, some, or only few cases, but these need to be validated through clinical research. The assumption that this is true stems from pre-scientific folk beliefs about “natural” remedies or religious notions that God has provided for the needs of human beings by packaging remedies for our ills in nature. These beliefs have not been validated scientifically despite the claims to the contrary. Many interesting hypotheses are advanced in the application for how herbal combinations could potentially be more effective or safer than isolated compounds, but these are just hypotheses, not the established fact claimed in the document.

The application goes on to respond to concerns about the use of folk myth and pre-scientific tradition rather than science in the use of herbal remedies. The ACVBM is clearly trying to mitigate the impression that herbalists rely primarily on “traditional knowledge” rather than science in their practice.

The ACVBM differentiates themselves by interest in the rich knowledge base of traditional botanical medicine use and ethnobotany combined with modern scientific, chemical, toxicological, pharmacological clinical application and research in a practice that could be appropriately termed rationale phytotherapy to distinguish from colleagues who may only embrace traditional findings or who may eschew scientific findings. This is an evidence-based system that encourages in vitro and in vivo studies to explain mechanisms of action, pathophysiology, pharmacokinetics and bioavailability as well as efficacy of botanical medicines.

This is the application of plant based medicine (supported by science and/or traditional use) to conventional diagnosis, multiple diagnoses and complex cases and to address individual signs and problem lists; or for prevention of disease by protecting organ health and /or optimizing animal health through actions not available with conventional drugs.

I certainly believe that the best hope for making effective use of the potential in plant compounds as medicines is in a strong scientific approach, one that views traditional use only as a weak foundation for hypotheses to test, not as a sufficient basis for clinical practice. I am, however, not convinced that the ACVBM as a whole truly embraces this view. I have investigated the public statements are claims of the members of the Organizing Committee in detail, and I have followed many of them for years. A couple seems genuinely interested in bringing scientific rigor to the field. Most, however, have been quite consistent in expressing the view that science is useful only when is supports their beliefs, derived primarily from personal experience and tradition, and that scientific invalidation of anything they “know” already is nearly impossible. Science is more of a marketing tool, to convince the skeptics, not a path to testing and questioning their own views rigorously and sincerely. There are hints of this even in this document, despite efforts to suggest agreement with the view than science is necessary and tradition merely a jumping-off point.

Veterinarians using botanical medicine have a patient centered approach, whereby the botanical medicines are selected based on the individual signs and pathophysiology as well as the diagnosis. So that two dogs with diabetes for example, may be treated with two different sets of botanical medicines.

What they don’t say here is that this “individualization” is not based on scientifically established knowledge but folk tradition, personal experience, and gut feelings.

The document also discusses various sources of information in detail, with an obvious effort to rationalize the role of tradition and personal experience in the absence of significant reliable scientific evidence. This is not inherently mistaken, since the same sources of information are used in conventional medicine, and we always have to balance the availability of information against its reliability. Personal experience is easy to find but highly unreliable. Consistent, high-quality clinical research is a lot better but a lot harder to come by.

Traditional use-
The bewildering variety of ethnoveterinary practices, ethnobotanical uses and folk practices around the world coupled with confounding aspects of cultural, placebo and other non-specific effects make reliable conclusions from any one tradition difficult. Frequently however, traditional use informs research and pharmacological activity is often found to be closely correlated. There are recurring themes in traditional medicine and persistent therapeutic approaches consistent with the use of “archetypal” chemical groups within plants.

Contrary to the implications here, traditional folk practices do not consistently or accurately predict the pharmacology or clinical effects of plant chemicals. The vast majority of traditional herbal uses have not been tested. Many of these, however, make absolutely no sense and so are unlikely to be a productive foundation for research. The idea of sympathetic magic, that if things which have superficial similarities these can predict deeper connections with therapeutic value, is clearly nonsense. Plants that may resemble a penis in some people’s eyes do not consistently turn out to be aphrodisiacs. Plants that are wrinkled like the brain or lobed like the lungs or that otherwise have some subjective superficial similarity to an organ in the body do not turn out to be plants with medical value for treating diseases of those organs, despite many folk medicine traditions holding this belief.

And systems which are arbitrary and unconnected with scientific reality are not good predictors of the medical value of plants used in those systems. Chinese medicine, for example, emphasizes the balance of imaginary forces, such as Heat, Wind, Damp, etc. Other systems, such as Western Humoral Medicine and the related Indian Ayurvedic approach, also emphasize balancing various forces to achieve or restore health. However, the forces involved are imaginary constructs that don’t correlate to physical reality. Most of the specific practices based on these theories don’t work, which is why thousands of years of using these ideas to guide medicine accomplished almost nothing in terms of improving health or fighting disease. The fact that the systems have similar concepts doesn’t make relying on the concepts, or the interventions derived from them, any more effective.

Collective clinical experience over decades-
There is also the clinical experience of veterinary practitioners to consider- thousands of educated veterinary practitioners worldwide prescribe herbal medicines in their work. This has advantages of being in a modern veterinary context. Veterinary practitioners of botanical medicine have written texts and taught other veterinarians to achieve repeatable results within the botanical framework.

Clinical experience is often the basis for treatment decisions in medicine. It is widely recognized in science-based medicine to be a shaky and unreliable foundation for decision-making compared to controlled scientific research, but often we lack research evidence to fully inform all the care we give. Unfortunately, we all tend to rely too much on experience, and it is common for clinicians to continue employing practices that seem effective to them based on their experience even when better scientific evidence has shown them not to work.

As a community, alternative medicine proponents are even less amenable to abandoning disproven methods than the science-based medicine community. The reverence for tradition and the relatively greater lack of research evidence to support alternative practices leads to a greater trust in experience even than conventional clinicians. Certainly, there are individuals who are committed to a rigorously scientific approach to herbal medicine. However, many of the leaders of the ACVBM have repeated expressed the view that science is predominantly a way of proving to others what they already know to be true from their own experience, rather than honestly testing their beliefs. Science does not yet support the claim here that herbal practitioners can achieve “repeatable results,” and unfortunately it is unlikely that the leaders of this group will change their minds and give up practices they believe to be effective even if good research evidence shows this.

The available published literature on phytochemistry and preclinical pharmacology (that frequently involve animal models exploiting mice, rats, rabbits and less so cats and dogs) of plant extracts is prolific. There are peer-reviewed journals devoted to the subject. Researchers have no doubt that nature is still the preeminent synthetic chemist and that in plants there are infinite reserves of fascinating constituents with actual and potential effects on health and disease. As such information accumulates it is often easier to better understand traditional uses of plants.

They do not however provide confirmation of a clinical effect; experience in practice is that the effect of the whole plant is rarely predicated on the effects of its parts. However such studies help to provide a rationale for the mechanisms of action of a herb.

For once, I agree completely. The bulk of research evidence concerning plant compounds is pre-clinical basic lab research. There is a lot that suggests these compounds may have significant medical value when used in the right way for the right problems. However, this kind of research does not justify the extensive use of herbal remedies in actual patients, which is precisely what the ACVBM is not only recommending but suggesting should be viewed as a legitimate medical specialty.

There are few well conducted placebo controlled double blind clinical trials on the effects of herbs in veterinary medicine. These are expensive to conduct and present methodological and logistical challenges. However, the evidence is accumulating in human medicine and rising in veterinary medicine.

Again, first half true, second half merely opinion. The overwhelming majority of the medical use of herbs in humans has not been proven in clinical trials to be safe or effective. Even some of the most widely used and promising herbal interventions that have been studied for decades, such as St. John’s Wort, have failed to show benefits that outweigh the risks. There is no repeatable, high-quality clinical trial evidence for any herbal prescribing in veterinary species. Such research must be conducted before we can even know if herbal medicine is useful, much less before we can call it a medical specialty.

No single source can absolutely confirm that herbs are a rational treatment strategy.Therefore, it is appreciated that herbs have been dismissed by many in the profession as the refuge of the uncritical. However, when all the sources of information come together and are integrated with pharmacological insights, something important happens; unique treatment strategies for treating notoriously difficult clinical problems become possible and the desire of the ACVBM is for animals to benefit from the efforts of this group to further develop the field.

Pure faith here. All of the evidence sources taken together suggest that some herbal products might be useful for some conditions in some cases, and these are worth testing. Nothing here shows convincingly that any herbal practice is dramatically effective or that herbal medicine has advanced to the point where it should be a medical specialty on a par with oncology, internal medicine, or other specialty areas in which the level of research evidence is dramatically higher.

The section on “philosophy” is especially interesting. A number of elements have been omitted, including the notion of non-physical spiritual or “energetic” forces involved in health and disease, which many of the leaders of the ACVBM have promoted elsewhere as integral to their practice. However, this section still shows some of the beliefs and assumptions behind herbalism which are problematic from the point of view of science.

The universal role of plants in the treatment of disease is exemplified by their use in all the major systems of traditional medicine and ethnomedicine irrespective of their underlying philosophical premise.

This may or may not be true, but it is irrelevant and an example of the appeal to popularity fallacy. Because something is widely practiced or believed has no bearing on whether it is true or should be accepted or adopted. The majority of pre-scientific folk medicine traditions also include specific religious or spiritual beliefs and practices, but that doesn’t mean these should be incorporated into science-based veterinary medicine.

The practitioner of botanical medicine regards the whole formula or whole extract as the “active ”component” in the therapeutic context.

The concept of polyvalent or multifaceted activity of the medicine is central to botanical medicine
-in the context of the advantage of chemical complexity -and even a single herbal extract is a natural multi agent medicine that can simultaneously target a range of desirable pharmacological effects.

The veterinary botanical practitioner prefers not just to prescribe chemically complex herbs, but often administers them in complex formulations, compared to conventional medicine preferring to prescribe a single drug. The practitioner chooses herbs or formulas for a cooperative or facilitating effect between the components to address therapeutic goals

Again, we see the commitment to the idea that plant chemicals are “natural” and that they are safer or more effective the more are mixed together in an herbal treatment, There is no compelling evidence for this belief, and it is contrary to much of the science of pharmacology that has led to so many medicine far more effective than any pre-scientific herbal treatment. There is a reason we take aspirin instead of chewing willow bark- the results is more predictable and effective. While there may be some combinations of herbal ingredients that work better or have fewer side effects when given together, this has to be proven for each by rigorous science, not simply accepted as fact based on traditional beliefs and unscientific theories.

Philosophically the veterinary botanical medicine practitioner practices conventional medicine but overlays that practice with the use of botanical medicines in a framework of botanical principles to expand their options for treatment of disease and optimizing health.

This is the standard claim of integrative medicine. It has a number of problems, which I’ve discussed in detail many times before. Basically, the addition of unproven or ineffective treatments to conventional scientific medicine doesn’t add value for the patient. Adding herbal medicine to conventional treatment will only help patients if those herbal treatments are shown to work. And any particular treatment that works should simply be part of medicine as a whole, not a separate category of “integrative medicine.”

If one is going to use alternative therapies, it is at least better not to use them as replacements for science-based medicine. However, even when practitioners of such therapies say this is what they do, there is reason to be skeptical. The same individuals often promote their treatments as safer and more effective than conventional medicine. If they believe this, wouldn’t they reach for these treatments first? Wouldn’t they likely tell their clients that their herbal treatments are better and safer, which would likely discourage these clients from pursuing conventional care? If they practice Chinese Medicine, as most of the members of the ACVBM leadership do, aren’t they going to evaluate patients and assign treatments based on the principles of this system? Since this is unscientific folk medicine, how is it compatible with a scientific approach to healthcare? The apparently simple claim that herbs aren’t meant to replace conventional treatment raises a lot of questions.

Practitioners appreciate traditional knowledge as just one potential source of information, when coupled with published research and clinical experience, herbs can be prescribed safely and effectively.

Of course, they recognize traditional folk knowledge as a reliable and important source of information, equal if not superior to scientific information about herbal remedies. This is a major danger of validating this approach as a specialty. It treats folk tradition as reliable knowledge, not merely speculations and beliefs that might or might not lead to useful insights and treatments. This attitude erodes the reliance on science that has supported all the tremendous progress in healthcare in the last 150 years and which has made us healthier that all the folk medicine of the preceding millennia.

The ACVBM also makes claims about the scientific basis of herbal medicine. I addressed some of these previously, and the updates to the application don’t add much to the previous discussion.

The ACVBM acknowledges the concerns regarding the scientific basis of veterinary botanical medicine. Where there are published scientific and clinical data supporting the overall safety and benefits of many plant medicines, the research might be dismissed as having methodological bias thus being of inferior quality to trials conducted on conventional drugs.

More accurately, the bulk of research on herbal treatments is pre-clinical, not evaluation of specific treatment approaches in specific groups of patients. The clinical research that does exist is methodologically weak and subject to bias compared with the research literature for conventional medicine. Therefore, very few of the day-to-day practices of herbal veterinarians are based on good science compared to those of conventional practitioners. This needs to be remedied before we can call herbal medicine a specialty.

However to be fair, this is also the case for clinical trials generally. for example in dogs and cats a review of  clinical trials uncovered a need for more high-quality studies. And more recently a cross sectional study of veterinary randomised controlled trials of pharmaceutical interventions funded by different sources was examined and it was found that a failure to report primary outcomes, justify sample sizes and the reporting of multiple outcome measures was a common feature in all of the clinical trials. The authors suggested that findings may be affected by the source of the funding and that some RCT’s provide a weak evidence base and targeted strategies are needed to improve the quality of veterinary RTCs to ensure there is reliable evidence on which to base clinical decisions.

The evidence base for conventional veterinary medicine is far weaker and more limited than it should be. It is also far stronger than the evidence base for veterinary herbalism. And the limitations in the former don’t erase or mitigate the limitations in the latter. The focus should be on building better evidence, not on designating some of the least evidence-based practices as a board-certified specialty.

By increasing awareness, the ACVBM will help the profession as a whole practice botanical EBM. Evidence based medicine however includes not just research, but also incorporates the needs and biases of the client and patient; and the clinical experience of the practitioner; in veterinary botanical medicine this last item has been developed without official support from the veterinary profession and its regulatory bodies, yet is essential to safe and effective practice.

This is a bit of a mischaracterization of evidence-based medicine. It is a system for recognizing the strengths and weaknesses of different kinds of evidence and for making the integration of scientific research evidence into daily practice explicit and formal. Clinical experience is acknowledged as both indispensable and highly unreliable as a guide to the safety and efficacy of treatments.

The ACVBM generally privileges tradition and experience over scientific evidence by claiming that herbal therapies can be broadly described as safe and effective and worthy of specialty status in the absence of any robust body of clinical research literature. The very act of seeking specialty recognition first and then promising to do the research later shows the lack of understanding that such research is not just nice to have but a necessity if we are to have any real confidence in our treatments.

If the ACVBM wishes to advance EBM and make the profession as a whole more evidence based, they would do better to form and fund a vigorous research community doing high-quality research to validate their core beliefs (such as the superiority of whole-plant remedies and mixtures over isolated compounds) and the clinical effectiveness of their treatments. Once a strong body of evidence is available, integration of such methods and recognition as a specialty would make sense.

Bottom Line
There are some positive changes in this updated application. It is clearly an attempt to allay concerns expressed about the lack of evidence for herbal treatments, the reliance on folk wisdom and tradition to guide herbalism, and the lack of a good foundation for treating herbalism as a medical specialty rather than simply evaluating and using herbal remedies scientifically within the existing framework of science-based medicine.

However, the changes to the document do not alter the fundamental objections I raised at the beginning of this post. Ultimately, there is not yet sufficient scientific evidence to validate most of the claims made for herbal remedies. The ACVBM leadership consists predominantly of individuals who espouse unscientific approaches to health and diseases, such as Chinese Medicine, and who have demonstrated the belief that science serves not to test the truth of their beliefs but to aid in marketing them to the rest of the profession.

The best thing this group could do, for herbal medicine and for veterinary medicine as a whole, would be to stop seeking recognition and formal acceptance of their existing practices and beliefs but instead to commit to a rigorous and objective scientific evaluation of those beliefs and practices. The talent and resources spent lobbying and promoting herbalism would be far more valuable if used to test herbal treatments in objective, unbiased scientific studies. If they don’t work, then we’ll know and we can move on. If they do work, then we’ll know and we can make use of them. Either way, veterinary medicine and our patients will benefit. Recognizing unproven folk beliefs and practices as a medical specialty will not advance veterinary medicine or benefit our patients.

Posted in Herbs and Supplements | 5 Comments

British Veterinary Body (RCVS) Accepts the Reality about Homeopathy that AVMA Couldn’t- It’s Nonsense!

Regular readers night remember a few years back when I was involved in promoting a non-binding policy statement from the American Veterinary Medical Association (AVMA) that would have acknowledged a simple and obvious principle: Vets should base their treatments on science and shouldn’t use ineffective, unscientific methods. Here is the text of that statement:

RESOLVED, that the American Veterinary Medical Association (AVMA) affirms that—

1. Safety and efficacy of veterinary therapies should be determined by scientific investigation.

2. When sound and widely accepted scientific evidence demonstrates a given practice as ineffective or that it poses risks greater than its possible benefits, such ineffective or unsafe philosophies and therapies should be discarded.

3. In keeping with AVMA policy on Complementary and Alternative Veterinary Medicine, AVMA discourages the use of therapies identified as unsafe or ineffective, and encourages the use of the therapies based upon sound, accepted principles of science and veterinary medicine.

4. Homeopathy has been conclusively demonstrated to be ineffective.

This resolution was based on a policy already adopted by the Australian Veterinary Association (AVA) and was consistent with the policies of other veterinary organizations, such as the British Small Animal Veterinary Association (BSAVA) Similar positions have been taken by numerous scientific and government bodies around the world (e.g. UK House of Commons Science and Technology Committee and National Health Service, the Australian National Health and Medical Research Council, the U.S. Federal Trade Commission, the European Academies Science Advisory Council, and others).

I wrote a white paper exhaustively detailing the evidence against homeopathy and demonstrated why the evidence presented in favor of the practice was not reliable. The AVMA’s own scientific body, the Council on Research, agreed there is no evidence to support the use of homeopathy. Nevertheless, the resolution was defeated by a 9:1 margin, illustrating the definitive preference for political expediency over science in AVMA policy.

Now, the status of the AVMA as an outlier for refusing to acknowledge the obvious truth that homeopathy is a worthless set of false beliefs and ineffective methods is further emphasized by a recent revision to the policy on complementary and alternative medicine byt the council of the Royal College of Veterinary Surgeons (RCVS), the regulatory body for veterinarians in the UK. Similar to the AVA policy and the resolution rejected by the AVMA, the policy reads as follows:

We have recently been asked questions about complementary and alternative medicines and treatments in general and homeopathy in particular. We would like to highlight our commitment to promoting the advancement of veterinary medicine upon sound scientific principles and to re-iterate the fundamental obligation upon our members as practitioners within a science-based profession which is to make animal welfare their first consideration.

In fulfilling this obligation, we expect that treatments offered by veterinary surgeons are underpinned by a recognised evidence base or sound scientific principles. Veterinary surgeons should not make unproven claims about any treatments, including prophylactic treatments.

Homeopathy exists without a recognised body of evidence for its use. Furthermore, it is not based on sound scientific principles. In order to protect animal welfare, we regard such treatments as being complementary rather than alternative to treatments for which there is a recognised evidence base or which are based in sound scientific principles. It is vital to protect the welfare of animals committed to the care of the veterinary profession and the public’s confidence in the profession that any treatments not underpinned by a recognised evidence base or sound scientific principles do not delay or replace those that do.

While there is some contortion of reasoning evident here to allow merely discouraging the replacement of real medicine with homeopathy, rather than actively opposing the use of homeopathy altogether, which is a concession to the political reality that some vets still employ it regardless of the lack of any reasonable basis for doing so, this is still a strong statement that veterinary medicine should be based in science and that homeopathy is not a scientifically legitimate practice. It is an important step forward in leaving behind faith-based folk medicine and emphasizing the importance of a science-based practice to the welfare of veterinary patients.

The growing chorus of organizations in medicine and government around the world rejecting homeopathy is in contrast to the depressing inability of organized veterinary medicine here in the U.S. to take such a simple, obviously correct stand in favor of what is ultimately best for our patients. We should be leading, and instead we are dragging our heels as the future of medicine, including veterinary medicine, continues moving towards scientific, evidence-based practices and away from the relics of pre-scientific folk medicine. Here in the US, one can argue that Chinese medicine, homeopathy, chiropractic, and other unscientific approaches may even be gaining ground despite their consistent failure to prove their worth. This is an unfortunate state fo affairs for our profession and our patients.

I am happy that the RCVS council has taken this step towards protecting the welfare of veterinary patients and the rights of animal owners in the UK to truly informed consent. I can only hope that we in the US will eventually overcome our resistance to any constraints on the autonomy of individual veterinarians and recognize that similar policies will serve the veterinary profession and the welfare of our patients far better than the current refusal to stand up against the anti-scientific nonsense of veterinary homeopaths and other purveyors of unscientific treatments and folk medicine. We owe this to the animals in our care and to our clients.

Posted in Homeopathy, Law, Regulation, and Politics | Leave a comment

Alternative Medicine Kills Cancer Patients

One of the most dangerous aspects of unproven or ineffective alternative therapies is the harm to patients when these are used in place of scientific medicine. While most proponents of alternative therapies generally recommend them as an addition to conventional treatment, despite the lack of evidence this improves care, some advocates of alternative medicine condemn conventional therapies and claim unproven alternatives are as good or better. This is especially common in relation to cancer treatment. Promoters of alternative medicine often very aggressively criticize or deride conventional cancer treatments as harmful and ineffective. A new study adds to existing evidence that turning to alternative treatments for cancer is a very dangerous choice.

Skyler B. Johnson, Henry S. Park, Cary P. Gross, James B. Yu; Use of Alternative Medicine for Cancer and Its Impact on SurvivalJNCI: Journal of the National Cancer Institute, Volume 110, Issue 1, 1 January 2018.

This study looked at human patients with a variety of cancers who chose to use various alternative treatments instead of conventional treatment. The patients were representative of the demographic characteristics typically associated with alternative medicine users: predominantly white, female, affluent, and educated. After controlling for other variables, alternative medicine use was associated with markedly lower survival times for every cancer evaluated except for prostate cancer, which tends to be very slowly progressive and much less likely to lead to mortality than most of the other cancers evaluated. The authors’ conclusions are quite clear:

we found that cancer patients who initially chose treatment with AM without CCT were more likely to die. Improved communication between patients and caregivers and greater scrutiny of the use of AM for the initial treatment of cancer is needed.

Of course, many advocates of alternative therapies will claim that this study doesn’t address the value of such treatments added to conventional medicine. However, it isn’t at all clear why therapies that evidently don’t work by themselves would add value when mixed with conventional treatments. And in any case, there isn’t yet any compelling evidence to support the integration of alternative cancer therapies with scientific medicine, and plenty of reasons to be skeptical of it. But this study reinforces existing evidence that turning to alternative medicine instead of scientific medicine when you have cancer is a potentially deadly choice.




Posted in General | 4 Comments

European Scientists Join Chorus of Government and Scientific Organizations Acknowledging the uselessness of Homeopathy

The evidence that homeopathy is ineffective for any and all medical problems and is nothing more than a placebo has grown steadily for over a century. Many reviews of the scientific research have been done, and despite hundreds of studies, no reliable evidence exists to support the core principles of homeopathy or the actual real-world benefits claimed by its practitioners. I reviewed this evidence in detail in support of a resolution before the American Veterinary Medical Association (AVMA) to declare homeopathy ineffective and discourage its use in veterinary patients. I also exhaustively examined the evidence provided in support of homeopathy and discussed why it is unreliable and unconvincing. The AVMA’s scientific advisory body, the Council on Research, agreed that “that there is no clinical evidence to support the use of homeopathic remedies for treatment or prevention of diseases in domestic animals.” Unfortunately, politics won out over truth, and the AVMA refused to acknowledge the obvious—that homeopathy is useless and veterinarians promoting it are deceiving animal owners.

Several scientific bodies around the world have reviewed the same evidence and come to the same conclusion. The United Kingdom House of Commons Science and Technology Committee conducted hearings and a thorough evidence review and came to stark and clear conclusions:

In our view, the systematic reviews and meta-analyses conclusively demonstrate that homeopathic products perform no better than placebos.

There has been enough testing of homeopathy and plenty of evidence showing that it is not efficacious. Competition for research funding is fierce and we cannot see how further research on the efficacy of homeopathy is justified in the face of competing priorities.

For patient choice to be real choice, patients must be adequately informed to understand the implications of treatments. For homeopathy this would certainly require an explanation that homeopathy is a placebo. When this is not done, patient choice is meaningless. When it is done, the effectiveness of the placebo—that is, homeopathy—may be diminished.

We recommend that the MHRA remove all references to homeopathic provings from its guidance other than to make it clear that they are not evidence of efficacy.

We consider that the way to deal with the sale of homeopathic products is to remove any medical claim and any implied endorsement of efficacy by the MHRA—other than where its evidential standards used to assess conventional medicines have been met—and for the labelling to make it explicit that there is no scientific evidence that homeopathic products work beyond the placebo effect.

It is unacceptable for the MHRA to license placebo products—in this case sugar pills—conferring upon them some of the status of medicines. Even if medical claims on labels are prohibited, the MHRA’s licensing itself lends direct credibility to a product. Licensing paves the way for retail in pharmacies and consequently the patient’s view of the credibility of homeopathy may be further enhanced. We conclude that it is time to break this chain and, as the licensing regimes operated by the MHRA fail the Evidence Check, the MHRA should withdraw its discrete licensing schemes for homeopathic products.

By providing homeopathy on the NHS and allowing MHRA licensing of products which subsequently appear on pharmacy shelves, the Government runs the risk of endorsing homeopathy as an efficacious system of medicine. To maintain patient trust, choice and safety, the Government should not endorse the use of placebo treatments, including homeopathy. Homeopathy should not be funded on the NHS and the MHRA should stop licensing homeopathic products.

Despite significant political resistance, including from members of the royal family, this message has been heard, and homeopathy has been banned from government-provided healthcare in the UK.

The government of Australia conducted a similar, exhaustive review over several years, with plenty of opportunity for input from supporters of homeopathy. This review also agreed with those that went before, concluding:

Based on all the evidence considered, there were no health conditions for which there was reliable evidence that homeopathy was effective. No good-quality, well-designed studies with enough participants for a meaningful result reported either that homeopathy caused greater health improvements than placebo, or caused health improvements equal to those of another treatment.

NHMRC concludes that there are no health conditions for which there is reliable evidence that homeopathy is effective. Homeopathy should not be used to treat health conditions that are chronic, serious, or could become serious. People who choose homeopathy may put their health at risk if they reject or delay treatments for which there is good evidence for safety and effectiveness.

Historically, the U.S. is less amenable to government regulation of health care than other developed countries. Homeopathy was grandfathered in to the FDA regulatory system by politicians in the 1930s, and since then there has been little political will to challenge the practice despite the powerful evidence against it. In 2016, however, both the Federal Trade Commission (FTC) and the FDA conducted reviews, with public comment, regarding their oversight of homeopathy. No report or action has yet resulted from the FDA review, and given the anti-science and anti-regulatory views of the current administration, it seems unlikely this will change any time soon. However, the FTC, which regulated advertising of healthcare products, did come out with a strong pro-science position on homeopathy last year:

For the vast majority of OTC homeopathic drugs, the case for efficacy is based solely on traditional homeopathic theories and there are no valid studies using current scientific methods showing the product’s efficacy.  Accordingly, marketing claims that such homeopathic products have a therapeutic effect lack a reasonable basis and are likely misleading in violation of Sections 5 and 12 of the FTC Act.

Nevertheless, truthful, nonmisleading, effective disclosure of the basis for an efficacy claim may be possible.  The approach outlined in this Policy Statement is therefore consistent with the First Amendment, and neither limits consumer access to OTC homeopathic products nor conflicts with the FDA’s regulatory scheme.  It would allow a marketer to include an indication for use that is not supported by scientific evidence so long as the marketer…effectively communicates to consumers that (1) there is no scientific evidence that the product works and (2) the product’s claims are based only on theories of homeopathy from the 1700s that are not accepted by most modern medical experts.

Essentially, what the FTC has said is that one can claim homeopathy works only if one admits that there is no scientific evidence for this claim and that it is based on pre-scientific folk beliefs with no validity.

The most recent addition to this chorus of official voices acknowledging the lack of benefit to homeopathy is the European Academies Science Advisory Council (EASAC), which recently issued a strong statement warning of the misleading nature of claims for homeopathy.

EASAC, the European Academies Science Advisory Council, is publishing the present Statement to reinforce and reiterate this extensive and well-founded critique and to encourage and support (i) policy makers in the EU in taking a more explicitly evidence-based approach to assessing the claims for homeopathy and (ii) all those interested in stimulating better public engagement with these contentious issues and in improving consumer’s rights to correct information.

…there is no robust, reproducible evidence that homeopathic products are effective for any known diseases, even if there is sometimes a placebo effect. Moreover, homeopathy can actually be harmful: by delaying or deterring a patient from seeking appropriate, evidence-based, medical attention and by undermining patient and public confidence in scientific evidence.

From analysis of the appropriately controlled, verifiable evidence base, any claimed efficacy of homeopathic products in clinical use can be explained by the placebo effect or attributed to poor study design, random variation, regression towards the mean, or publication bias…The scientific claims made for homeopathy are implausible and inconsistent with established concepts from chemistry and physics.

The promotion and use of homeopathic products risks significant harms as mentioned above. In addition, homeopathy raises issues of concern for patient informed consent if health practitioners recommend products which they know are biologically ineffective. There are also potential safety concerns for homeopathic preparations because of poorly monitored production methods.

  • There should be a consistent regulatory requirement for claims for the efficacy, safety and quality of all medicinal products to be based on verifiable and objective evidence, commensurate with the claims being made. The necessity for robust data applies to products for both human and veterinary medicine.

  • Public health system budgets are under increasing pressure. Evidence-based public health systems should not offer reimbursement for homeopathic products and services unless they are demonstrated to be efficacious and safe by rigorous testing.

The growing willingness of scientists, individually and through their organizations, and of regulatory bodies to confront pseudoscience and unscientific nonsense like homeopathy is an encouraging sing, and it is beginning to have an impact, as seen in the withdrawal of NHS support for homeopathic treatment. Ultimately, the more willing we in science are to challenge unscientific claims and methods and to take the time to explain the evidence to people, the more the public will be able to make sound, fully informed healthcare choices, which is what this blog is all about.

Posted in Homeopathy | 3 Comments

American Animal Hospital Association (AAHA) 2017 Canine Vaccination Guidelines

In previous discussions of vaccination recommendations, I have referenced several clinical guidelines that review the existing evidence and provide recommendations for vaccination. The American Animal Hospital Association (AAHA) and American Association of Feline Practitioners (AAFP) guidelines are quite extensive and useful documents in making decisions about vaccination. AAHA guidelines are, unfortunately, usually prepared by small groups of experts with little transparency, and they are not always a model of evidence-based guideline development (for a great model, see the RECOVER guidelines for small animal CPR). That said, the vaccination guidelines do a good job of summarizing the complex and sometimes contradictory evidence and making reasonable recommendations.

AAHA has update the canine vaccination guidelines, and has presented them in a new form. The 2017 AAHA Canine Vaccination Guidelines are now primarily an online document divided into sections that make finding the answer to specific vaccination questions quite easy. In terms of providing a summary of existing vaccine science and giving a general overview of the issues, the web-based format is clunky and harder to use than a traditional journal article. But in terms of giving direct answers to questions vets and dog owners typically have about when and how to use specific vaccines, the format works well.

The new guidelines also add detail to subjects only lightly discussed in the previous version, including the use of antibody titers to guide vaccination and how to handle animals with uncertain vaccine histories or overdue for boosters of vaccines given previously.

There is nothing revolutionary or earth-shattering in the new guidelines, and they will undoubtedly not satisfy the concerns of those with deep anxieties or objections to routine vaccination practices. The recommendations are very similar to previous versions, and there will be few changes for those of us who have been following these guidelines in the past. Thorny questions like how often, or if, boosters of core vaccines should be given are not always directly answered.

The previous guidelines summarized the evidence that, for example, vaccination for canine parvovirus (CPV) and canine distemper (CDV) should provide immunity for a minimum of three years and likely protects most dogs for at least 5-7 years and possibly longer (when given properly as a series to puppies with a booster at about one year). The currently guidelines recommend intervals for these vaccines of “three years or longer”, which leaves the exact interval to the discretion of vets in practice. This makes sense in many ways, since the risks and benefits of vaccination for individual animals depends on exposure risk, lifestyle, health, medical treatment, and many other variables. Ultimately, there is no single right answer for every dog.

Unfortunately, it is easier for most vets to choose an arbitrary recommendation to make for all their patients. Right now, many choose three year intervals for these vaccinations because that number was specifically suggested in the AAHA guidelines. When I have suggested longer intervals might be appropriate, many of my colleagues are understandably wary of deviating from what all the major veterinary schools and most other practices are doing for fear of being blamed for any failure of protection that might occur. And, of course, none of this will satisfy those who think little or no vaccination is necessary at all.

Despite the inevitable compromises and limitations in the evidence, however, the AAHA guidelines are an excellent resource for vets and dog owners wishing to make rational, science-based decisions about how best to protect dogs from vaccine-preventable disease.

Posted in Science-Based Veterinary Medicine, Vaccines | 22 Comments

Pets deserve Evidence-based Medicine Too!

Here’s a recent interview I did for NPR on the SkeptVet Blog and the need for skeptical, evidence-based medicine for our animal companions.

Why does the world need skeptical veterinarians?

Pet owners need to know the pros and cons of health care options for their pets to make good decisions. “Skeptic” doesn’t mean someone who automatically rejects new or unfamiliar ideas. It’s someone who refrains from judging a claim until they have examined the evidence dispassionately — someone who gives preference to scientific evidence over personal experience, anecdote, tradition or history.

Posted in Presentations, Lectures, Publications & Interviews | 16 Comments

Discussion of the ACVBM Application for Specialty Status for Herbal Veterinary Medicine

About six months ago, I reported on the application of a group of veterinarians belonging to the American College of Veterinary Botanical Medicine (ACVBM) for status as a medical specialty group. I explained the main reasons why, despite the potential value of herbal medicine, such status is not warranted at this time:

  1. There is very little high-quality or reliable scientific evidence to support the use of herbal products in veterinary patients.
  2. Herbal prescribing is dominated by Chinese Medicine, Ayurveda, and other unscientific folk belief systems, and those proponents who take a more scientific approach are a small minority generally unwilling to reject the claims or methods of alternative herbal medicine.
  3. Herbal products are unregulated, inconsistent and unpredictable in their chemical composition, frequently contaminated with toxins or even undisclosed pharmaceutical drugs, and almost none have been properly tested for safety or efficacy. There is ample evidence of serious harm to human patients from herbal products. The ACVBM supports industry self-regulation rather than the kind of government oversight accepted as necessary for pharmaceutical medicines without any sound reason for doing so.
  4. The majority of the leadership of the ACVBM are dedicated proponents of alternative medicine, not only for herbal products but homeopathy, acupuncture, energy medicine, and many other unproven or pseudoscientific practices. Many have said clear and troubling things that display a contempt for science and science-based medicine and a desire to use the appearance of scientific methods to gain acceptance for alternative practices. This makes it very likely that approval of the ACVBM as a specialty board would serve as a Trojan horse for the legitimization of other alternative therapies.
  5. The potential of herbal medicines would be better explored from a rigorously scientific approach involving specialists in pharmacology, toxicology, nutrition, epidemiology, and other existing medical specialties.

The deadline for public comment on the application is September 1. As this date approaches, there has been more discussion of this issue. The Veterinary information Network (VIN) News Service recently published an article on the debate in which I and other skeptics, as well as several proponents of herbal medicine are quoted at length.

The American College of Veterinary Internal Medicine (ACVIM) has taken a public position opposing the ACVBM application.

Proponents of the application have also been active, including efforts to gain support from the American Holistic Veterinary Medical Association (AHVMA), the leading advocacy group for alternative veterinary medicine . This actually helps to support and illustrate my objection #4 above. Even members of the ACVBM who claim to support a scientific approach and eschew the alternative roots of herbal medicine are providing links to the AHVMA templates for letters supporting the petition. Herbal medicine is still inextricably linked to alternative medicine, and this will not be fixed by setting up a specialty board run by alternative practitioners.

Similarly, the current president of the ACVBM, Dr. Ihor Basko, has made this statement in his appeal to supporters to write letters in favor of the petition:

Surprisingly there is much opposition to the college, mostly from veterinarians. It also appears that the pharmaceutical industry has hired “trolls” disguised as pet owners to write letters in opposition to the college.

Dr. Basko is an advocate of Chinese Medicine and many varieties of unscientific medical practices, and this sort of consipracist nonsense is typical of the ideology and rhetoric of the alternative medicine community. To suggest the ACVBM will be a rigorously and strictly scientific group when practitioners like Dr. Basko dominate the leadership is disingenuous and not convincing.

I encourage anyone dedicated to truly science-based veterinary medicine to write or email the American Board of Veterinary Specialities before September 1 and declare your opposition to this application. I have provided the contact information and a sample letter below:


American Board of Veterinary Specialties
c/o Mr.David Banasiak
1931 N. Meacham Rd, Suite 100
Schaumburg, IL, 60173

Dear Mr. Banasiak:

I am writing to oppose the recognition of the American College of Veterinary Botanical Medicine (ACVBM) as a veterinary specialty organization. The ACVBM does not meet the core criteria set forth by the ABVS, and recognition would not be in the best interests of animal owners nor the veterinary profession.

Botanical medicine is not recognized as a medical specialty, in human or veterinary medicine, in the U.S., Europe, Australia, or most other scientifically advanced nations because the research evidence concerning herbalism and botanical remedies does not support this status. Prescribing practices are largely untested and based on folk medicine beliefs and traditions, and most herbal products are untested and un-regulated. Very few herbal therapies have been validated by the type of high-quality clinical trial evidence typically required for pharmaceutical medicines. Problems with mislabeling and contamination by toxic adulterants and pharmaceuticals is frequently reported for herbal products, with documented harm to patients. While there is great potential for medicinal use of plant-derived compounds, this potential can best be realized through pharmacognosy and other conventional forms of scientific research under the auspices of clinical pharmacology, toxicology, and other existing medical specialties.

The primary distinction the ACVBM offers between its approach and current conventional research and application of herbal remedies is the use of “traditional knowledge” to guide herbal prescribing. This means that the theories and practices of folk medicine traditions are considered sufficient to guide the use of herbal medicines, even when controlled research evidence is unavailable or contradicts traditional theory and practice. Almost none of this “traditional knowledge” has been validated by controlled research, and much of it is incompatible with established scientific principles and knowledge.

Illustrating the reliance of the ACVBM on unscientific principles is the affiliations and practices of the members of the ACVBM Organizing Committee. Nearly all are affiliated with the Chi Institute or other Chinese Medicine organizations, and most are practitioners of Traditional Chinese Medicine (TCM). TCM is an alternative system for understanding health and disease which is entirely independent from, and inconsistent with, science-based medicine. It views disease as arising from imbalances of mystical forces, such as Chi or Yin and Yang, and metaphorical humors such as Wind, Damp, Heat, and so on. Diagnoses such as “Rebellious Chi” or “Excess Wind” are made based on behavioral and historical information, tongue color and texture, pulse quality, and other traditional means. These diagnoses are then used to guide the use of herbal products, which are categorized in their effects by taste, appearance, and historical use rather than any scientific analysis of their components or physiologic effects. TCVM is not a specialty area within scientific veterinary medicine, it is an alternative to it. Recognizing the ACVBM would effectively identify TCM herbalism as a legitimate scientific medical practice without appropriate evidence to support this status.

Additionally, a majority of the ACVBM leadership is also affiliated with the American Holistic Veterinary Medical Association (AHVMA), and many have served in the leadership of this group. The AHVMA promotes and defends every type of alternative medicine, from herbalism and acupuncture to homeopathy and faith healing. Most of the Organizing Committee members promote or utilize numerous alternative therapies other than herbal medicine, and many have been publicly critical of conventional and evidence-based medicine and have recommended greater reliance on traditional knowledge and personal experience. These views do not support a rigorous scientific standard for developing safe and effective therapies and would not promote more evidence-based and higher-quality patient care.

The best way to develop the potential of plant-based medicines is to continue rigorous scientific research into herbal remedies, based on established scientific principles and methods. This progress can best be accomplished through the existing veterinary specialty areas. Traditional use may suggest testable hypotheses, but it is not a reliable guide for prescribing. Recognition of the ACVBM would be counterproductive in encouraging folk medicine-based approaches and in giving the ABVS imprimatur of scientific legitimacy to theories and practices which do not merit it. This would mislead veterinarians and animal owners and encourage the promotion of unscientific alternative practices.

Posted in Herbs and Supplements | 5 Comments

Evidence Update: Biologic Plausibility of Curcumin (Turmeric) Very Low

In 2013, I wrote about the burgeoning popularity of the spice turmeric as a medicinal herb. At the time, my conclusions were:

Overall, there is no compelling clinical evidence in humans supporting any use of curcumin or other turmeric compounds…There is virtually no clinical research in companion animals, and what there is does not support claims of benefit from turmeric compounds. Finally, the limited research to date suggests a few potential risks but the significance of these is unclear.

Since then, there have been many additional in vitro or lab animal studies, but no significant clinical trials in companion animal species. The pre-clinical research continues to find interesting biological activity of curcumin and other turmeric compounds which might, or might not, lead to clinically useful effects. At this point, there isn’t much new evidence that supports altering my previous conclusions.

However, one new review has looked at the biologic plausibility of curcumin, which is one factor in assessing the potential medicinal applications. This paper, somewhat surprisingly, suggests that the basic biochemistry of curcumin makes it unlikely to be a clinically useful remedy.

Nelson KM. Dahlin JL. Bisson J. et al. The Essential Medicinal Chemistry of Curcumin J. Med. Chem. 2017;60:1620?1637.

The authors review the pre-clinical and clinical trial literature for curcumin with an eye to features that would make the compound a better or worse candidate medicine. They conclude that its basic biochemical features make it unlikely to be useful but highly likely to generate false positive results if not tested with a clear understanding of its properties:

The likely false activity of curcumin in vitro and in vivo has resulted in >120 clinical trials of curcuminoids against several diseases. No double-blinded, placebo controlled clinical trial of curcumin has been successful. This manuscript reviews the essential medicinal chemistry of curcumin and provides evidence that curcumin is an unstable, reactive, nonbioavailable compound and, therefore, a highly improbable lead.

Curcumin…has shown excellent promise in early testing (in vitro), even though this testing may have been bedeviled by design problems that led to several misfires. The structure of 1 suggests that it might be unstable in a biological setting, and in fact, it is: both its in vitro and in vivo stabilities are abysmal…relative to commercial drugs.

To our knowledge, [curcumin] has never been shown to be conclusively effective in a randomized, placebo-controlled clinical trial for any indication. Curcumin is best typified, therefore, as a missile that continually blows up on the launch pad, never reaching the atmosphere or its intended target(s).

While these failures would normally end further research on its use as a therapeutic, they apparently have not deterred researchers interested in its development.

Given its low systemic bioavailability, we remain highly skeptical that an oral dose of 1 can ever be effective in human clinical trials that are translated from reports of in vitro activity… the lack of any observed efficacy of oral curcuminoids in clinical trials where it was given in high doses does not bode well for these alternative hypotheses of therapeutic efficacy.

Unfortunately, no form of curcumin, or its closely related analogues, appears to possess the properties required for a good drug candidate (chemical stability, high water solubility, potent and selective target activity, high bioavailability, broad tissue distribution, stable metabolism, and low toxicity). The in vitro interference properties of curcumin do, however, offer many traps that can trick unprepared researchers into misinterpreting the results of their investigations.

While such an analysis does not entirely preclude curcumin eventually being a useful remedy, it does reduce the likelihood of this, especially given the failure of any dramatic clinical trial results suggesting a significant real-world benefit.

Posted in Herbs and Supplements | 16 Comments

Evidence Update: Feline Facial Pheromone Doesn’t Reduce Stress or URIs in Shelter Cat Study

I have written numerous times about the use of pheromones to reduce stress and stress-related problems in cats and dogs (1, 2, 3). Overall, the evidence for these products is weak, and it is likely they have little to no meaningful benefit. A new study of pheromone therapy in shelter cats appears to support this conclusion.

Chadwin RM. Bain MJ. Kass PH. Effect of a synthetic feline facial pheromone product on stress scores and incidence of upper respiratory tract infection in shelter cats. J Am Vet Med Assoc. 2017 Aug 15;251(4):413-420.

In this study, several hundred shelter cats were exposed to a pheromone diffuser or a placebo diffuser and assessed in terms of behavioral indicators of stress and incidence of upper respiratory infections (URI), which appear to occur more commonly with increases stress.

The methodology was generally sound, with appropriate randomization, blind assessment, and placebo controls. The study was under-powered, which means it is possible that a small difference between the groups may have not been detected in the statistical analysis. The authors also performed a large number of statistical comparisons of many variables. This is an approach which can raise the risk of falsely positive findings.

The findings, however, were pretty consistently negative. No difference was seen in stress scores or in the occurrence of URI between cats exposed to the pheromone and those exposed to the placebo. No evidence of harm from the pheromone treatment was seen, though this was not specifically sought.

As usual, no single study should be taken as the definitive answer to any medical question. However, in light of the fact that pheromones have been in use and studied extensively for decades and strong, consistent evidence of significant benefits has not been seen, this study strengthens the argument that these products do not, in fact, provide such benefits.



Posted in Science-Based Veterinary Medicine | Leave a comment

Evidence Update: Potential Associations Between Neutering and Immune System Disorders

The risks and benefits associated with neutering are a complex and active area of research and debate in veterinary medicine. I have written several extensive summaries of the literature and numerous articles here evaluating the burgeoning research evidence. One subject that has seldom come up is the potential influence of neutering on the occurrence of diseases of the immune system. Although it is well established that sex hormones have variable and significant effects on the immune system, and that there are frequently sex differences in the risk of autoimmune and immune-mediated diseases, which suggests that sex hormones influence this risk, there has not been much direct research evaluating the relationship, if any, between neutering and the occurrence of diseases involving the immune system. A retrospective study published last year attempts to add to the very limited evidence previously published on this subject.

Sundberg CR. Belanger JM. Bannasch DL. et al. Gonadectomy effects on the risk of immune disorders in the dog: a retrospective study. BMC Veterinary research. 2016;12:278.

The authors looked back at a university veterinary college database of patients seen over a 15-year period. They first identified diagnoses of a number of conditions involving the immune system an then looked for differences in the occurrence of these conditions between males and females and between intact and neutered animals. The conditions evaluated included:

Atopic dermatitis (atopy or environmental allergies)
Autoimmune Hemolytic Anemia (AIHA)
Myasthenia gravis (CMG)
Hypoadrenocorticism (ADD or Addison’s disease)
Immune-mediated polyarthropathy (IMPA)
Immune-mediated thrombocytopenia (ITP)
Inflammatory bowel disease (IBD)
Lupus erythematosus (systemic SLE and discoid DLE)
Pempigus complex (PEMC)

These conditions were chosen because they all occurred in at least 0.1% of the dogs in the database. These are the most common of a group of conditions which are still, as a whole, usually very uncommon. The authors also looked at the occurrence of pyometra or uterine infections, a condition known to be common in intact females and to be prevented by neutering, which served as a control condition.

The study found an association between being neutered and the occurrence of 7/11 of the autoimmune diseases evaluated: ATOP, AIHA, ADD, HYPO, ITP, IBD, and LUP. Of these and increases occurrence of LUP was only seen for females, and for females appeared to be at greater risk than males for all of the conditions except ADD.

For those animals in which the age of neutering was known, no association was found between disease occurrence and age at neutering.

As expected, pyometra was significantly more common in intact females compare to neutered females.

While these data do suggest that there may be some protective effect of sex hormones against autoimmune disease, the authors correctly identify a number of important caveats:

  1. Retrospective studies are NEVER proof of a causal relationship because there are too many variables that cannot be identified or controlled.
  2. The study population at a university hospital is often very different from the population in general, which makes it unreliable to extrapolate associations from one to the other. For example, atopic dermatitis is one of the most common conditions seen in dogs with rates up to 19% reported. This study population only had a rate of 1.8%, which is much lower than expected. In general, university patients are much sicker and have more unusual conditions than typically seen in the general pet population, so they aren’t always good examples of health and disease in more normal populations.
  3. Even if there is some causal role of neutering in the occurrence of these conditions, it is not the only or primary cause. Genetic variables and environmental triggers have been identified for many of these conditions, so any role played by neutering is just one of multiple factors to consider in the genesis of these conditions.
  4. These conditions are mostly quite uncommon, and any increase in risk that might be associated with neutering has to be balanced against the established benefits of neutering to the health of individuals and to the pet population as a whole.

Bottom Line
This paper adds some useful information to the complex and ongoing assessment of the risks and benefits of neutering. It does not establish that neutering causes autoimmune disease, and it is not justification for dramatic changes in neutering practices. However, it support continued study and consideration of the potential negative effects of neutering on the immune system.

Posted in Science-Based Veterinary Medicine | 6 Comments