Selected Effects of Neutering in German Shepherd Dogs

As part of my ongoing surveillance of evidence concerning the benefits and risks of neutering, I have identified a new study on the subject.

Hart, B. L., Hart, L. A., Thigpen, A. P. and Willits, N. H. (2016). Neutering of German Shepherd Dogs: associated joint disorders, cancers and urinary incontinence. Veterinary Medicine and Scienc. doi: 10.1002/vms3.34

This study is a retrospective that looks through the records of the veterinary hospital at the University of California at Davis. It is a product of the same research group that has produced several other similar studies I have also reviewed. These earlier studies found some interesting differences between even closely related breeds, such as Labrador retrievers and golden retrievers, which suggests that generalizations applicable to all dogs regardless of breed are unlikely to be very reliable. This is always frustrating, since simply, universal rules are more appealing and easier to apply than nuanced, complicated risk/benefit calculations, but science often shows us that nature is more complex than we might wish. This study illustrates again the importance of breed in evaluating the potential effects of neutering.

This study includes some of the same limitations I have discussed when evaluating previous studies by this group. For example, except when evaluating mammary cancer, the authors did not consider diagnoses in dogs over eight years of age. Their rationale is that the effects of neutering might be swamped by other factors in older dogs, making them harder to detect. While this may be true, it is an assumption that has not been demonstrated to actually be true. And since overall health and disease occurrence, mortality, and longevity are the outcomes of real interest to pet owners, not just diseases that occur in the first eight years of life, using a cutoff like this can misrepresent the real importance of neutering. If, as some evidence suggests, neutered animals live longer overall than intact animals, for example, then neutering might still be the better choice even if one can show it causes more of some types of disease in the first eight years of life.

And a I have discussed in the context of their previous papers, and the authors themselves acknowledge, this study uses records pertaining to dogs seen at a university veterinary hospital. The people and patients who go to vet schools for treatment differ in a number of ways from those who don’t, and these differences may effect the diseases they get and the impact of neutering on health. This doesn’t invalidate the data or conclusions, of course, but it means we must be cautious in extrapolating these to first opinion practice populations.

The authors evaluated the impact of neutering before 6 months of age, between 6 and 11 months of age, between 1 and 2 years of age, and between 2 and 8 years of age on the occurrence of various disease compared with un-neutered dogs. Here is a brief summary of the findings:

  • Neutering before 12 months of age (combining the < 6 months group and the 6-12 months group) was associated with a higher risk of cranial cruciate ligament ruptures in both neutered males and females compared with intact dogs. This is similar to the findings for golden retrievers, though no increase in risk was found for Labrador retrievers except in males neutered before 6 months of age.
  • Neutering, regardless of age, was not associated with any difference in the risk of hip dysplasia or elbow dysplasia. In contrast, similar earlier studies did find an increase in hip dysplasia risk in male golden retrievers neutered before 12 months of age and an increase in risk for female Labrador retrievers neutered before 2 years, but no increase for female goldens or male labs. As always the devil is in the details.
  • Neutering, regardless of age, was not associated with any increase in risk of any cancer. Some earlier studies have found inconsistent and complicated increases in the risk of some cancers that vary with age at neutering, sex, and breed. Broad generalizations about neutering and cancer risk seem difficult to support given this variability in the data.
  • No statistically significant difference was found between neutered and intact females in the risk of mammary cancer. However, very few cases were found (only 14 out of 450 dogs), possibly due to the cutoff of 11 years of age used.
  • Urinary incontinence was significantly more common in females neutered between 6 and 11 months of age than intact females. Differences for other neutering ages and intact females were not significant, but there were no cases of incontinence in intact females.
  •  All cases of pyometra were in intact females, of course. This only occurred in about 2.5% of the females, However, since this disease becomes more common with age and the dogs were only evaluated up to 8 years of age, this likely under-represents the real risk of this problem in intact females.

Overall, this study adds yet another small but useful bit of information for vets and dog owners to consider in making decisions about neutering. It emphasizes yet again that the impact of neutering differs significantly between breeds, and general rules cannot be reliably applied to all dogs.



Posted in Science-Based Veterinary Medicine | 6 Comments

How to Prove a Therapy is Effective Even When its Not

Over the years, I have written a lot about how we come to hold and maintain false beliefs in medicine. Perhaps the lion’s share of this lies in anecdotes, which are powerfully persuasive despite all the sources of bias and error they contain that actually make their conclusions highly unreliable. Here are some of the articles I have posted making this point:

Why We’re Often Wrong Testimonials Lie
The Role of Anecdotes in Science-Based Medicine
Why We Need Science: “I saw it with my own eyes” Is Not Enough
Don’t Believe your Eyes (or Your Brain)

However, scientific research, while more trustworthy than our personal experiences and the stories we tell, can also be misleading and influenced by many of the same sources of cognitive bias and error that bedevil anecdotes and clinical experience. I have written about this subject before:

Can We Trust Published Scientific Research?

I recently came across a brilliant paper that illustrates how clinical trials, one of the best single tools available for evaluating medical treatments, can be misused to generate the appearance of scientific support for treatments that don’t actually work. The practices described in this paper are all too common in every area of medical research. Sadly, they are especially prevalent in veterinary clinical studies. And the paper provides an almost perfect description of the great majority of research done in complementary and alternative medicine, which is why so much of the literature in that field is truly more marketing than good science.

As I have argued before, this is often the explicit intent of researchers promoting alternative therapies, such as the American Holistic Veterinary Medical Association and its affiliates. However, the misuses of clinical trials, and of statistical analysis of trial data is unfortunately a blight on mainstream medical research as well. Everyone interested in the truth in medicine would do well to read this paper.

Cuijpers and I. A. Cristea How to prove that your therapy is effective, even when it is not: a guideline. Epidemiology andPsychiatric Sciences, Available on CJO 2015 doi:10.1017/S2045796015000864

The authors describe, clearly and in an engaging way, many practices in clinical trial design and conduct that can lead to false positive conclusions. Most are driven, ultimately, by the passionate belief of researchers in the a priori truth of their hypothesis. The following table succinctly describes the major issues.

2015 Cuijpers table 1

Their conclusions are equally succinct and worth bearing in mind when conducting or reading clinical trial research.

In this paper, we described how a committed researcher can design a trial with an optimal chance of finding a positive effect of the examined therapy….We saw that a strong allegiance towards the therapy, anything that increases expectations and hope in participants, making use of the weak spots of randomised trials (the randomisation procedure, blinding of assessors, ignoring participants who dropped out, and reporting only significant outcomes, while leaving out non-significant ones), small sample sizes, waiting list control groups (but not comparisons with existing interventions) are all methods that can help to find positive effects of your therapy. And if all this fails you can always not publish the outcomes, and just wait until a positive trial shows what you had known from the beginning: that your therapy is effective anyway, regardless of what the trials say.

Of course, whenever the weaknesses in scientific research are discussed, this provides an excuse for some to claim that science is inherently unreliable, or at least no more reliable than anecdote or personal experience, and thus we can safely do without clinical trial research. It is very important for us to understand that this is untrue. The purpose of identifying the weaknesses in science is to help find ways to make scientific research better and more reliable. It has already proven itself greatly superior to trial-and-error and anecdotal evidence.

Lest we despair, there here are some previous discussions about the ways in which we can improve scientific research, including choosing what to study more rationally, designing, conducting, and reporting trials more effectively, and minimizing the influence of financial bias.

Evidence-based Medicine Separating the Wheat from the Chaff

Making Medicine Better: Support Registration of All Trials in Veterinary and Human Medicine

Guidelines for Minimizing Commercial Influence in Veterinary Medicine

Ioannidis JPA (2014) How to Make More Published Research True. PLoS Med 11(10): e1001747.

ioannidis how to make research more true box 1


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Neutering and Cancer Risk In Cats

I have written extensively about the scientific evidence concerning the benefits and risks of neutering. Overall, the data is complex, and significant effects of neutering on specific health risks are rarely definitively demonstrated. One of the most controversial issues, the influence of neutering on cancer risk, illustrates this. Some cancers are more common in neutered animals, some are more common in intact animals, and the effect of neutering on cancer risk varies with sex, breed, age at neutering, and possibly other factors. When looking at the issue in cats, we have the added challenge of far less research data than is available for dogs. However, one new study has added a bit more information to help evaluate the subject.

Graf R, et al. Swiss Feline Cancer Registry 1965-2008: the Influence of Sex, Breed and Age on Tumour Types and Tumour Locations, Journal of Comparative Pathology (2016).

There are a number of limitations to this paper that have to be considered. Laboratories in Switzerland that analyze tumors contributed data to a central registry. The study reports an analysis of data collected in this registry over a very long period of time. This often creates problems since definitions of disease and the behavior of animal owners and veterinarians, in terms of relevant issues like how likely to diagnose and treat cancer, submit samples to laboratories, and so on, change over time. The data collected at the beginning of the time period analyzed may or may not be truly comparable to the data collected later.

Also, use of the registry is voluntary, so it is not clear how representative this data is of the overall cat population in Switzerland, much less anywhere else. And exactly how the data is collected and processed is not reported in the paper, and many important terms are not well defined. For example, it is not clear how cats are classified as neutered or intact, and there is no discussion of the age at which neutered cats are neutered, which has been an important factor in other studies. So evaluating potential sources of bias and error effectively is impossible, and therefore this is the sort of data that have to be taken with some skepticism.

Nevertheless, given the paucity of data on the effect of neutering on feline cancer risk, this paper is a useful addition. The portion of the report that relates to neuter status is contained in the following two tables:

Graf 2016 Table 1

Graf 2016 Table 2

There are several interesting patterns that can be discerned in these tables. The first is that there is a pretty consistently higher cancer risk in neutered cats compared with intact cats. This ranges from about 25-50% higher for most cancer types, though there are some for which there is no apparent difference in risk (fibrosarcomas for males and adenomas/adenocarcinomas for females).

Looking at specific tumor locations, the general pattern is for neutered cats to have a higher risk of tumors in some locations (skin, gastrointestinal tract, cardiorespiratory system, and oral cavity) and a lower risk for mammary tumors (in both males and females, though females are at much higher risk overall for mammary tumors than males, whether intact or neutered). If these differences are consistent in other study populations, it might help shed more light on the specific mechanisms by which sex hormones could be protective against some cancers while neutral or even a risk factor with respect to others.

While there are many limitations and caveats to these data, they do suggest a pretty consistent mild-moderate increase in cancer risk associated with neutering in cats. As always, this has to be balanced against the other health risks and benefits associated with neutering, as well as other important issues, such as the ethical and environmental impact of cat reproduction. This paper emphasizes the complexity of biology and the multifaceted potential effects, both good and bad, of any intervention which significantly effects the physiology of our animal companions and patients.

Posted in Science-Based Veterinary Medicine | 2 Comments

The Unfortunate Role of Alternative Medicine in the Animal Hospice Movement

I first wrote about the subject of hospice care for animals in the first year of this blog, 2009. I feel strongly that there is a need to adapt the concepts of hospice and palliative care developed in human medicine to the needs of veterinary patients. While euthanasia is, thankfully, an option for most terminally ill veterinary patients, this does not obviate the need for appropriate relief of the suffering of our patients and for thoughtful conversations with pet owners about death and how to approach end of life issues.

One of my favorite authors, Atul Gawande, has written a brilliant book called Being Mortal, which looks at the successes and failures of the medical system in America when handling the end of life. One of the bright spots is the role of hospice care in providing a comfortable, meaningful, and dignified end to human life. Our veterinary patients deserve the same.

However, while I have great respect for the vets who are trying to bring the benefits of hospice care to animals under veterinary care, I have some concerns as well. One is the role of spiritual questions in animal hospice care. Because the end of life brings our spiritual beliefs to the fore, the beliefs of animal owners are certainly relevant to how a veterinarian manages the care of a patient at the end of life. In the most extreme cases, euthanasia may not be an option at all due to some people’s religious beliefs. While I may disagree with such a position, it is not the role of a vet to challenge a client’s personal beliefs in this situation. It is, of course, a vet’s role to act as an advocate for the welfare of the patient. Hospice care provides a way to protect the welfare of the patient even when there may be a conflict between the needs of the patient as the veterinarians sees them and the choices of the animal owner.

However, there are some in the animal hospice community who actively insert their own personal spiritual beliefs into the practice of veterinary hospice care, and this is troubling. The International Association of Animal Hospice and Palliative Care (IAAHPC) specifically supports, for example, the right of a hospice veterinarian to “have a

principled moral objection to euthanasia, in general, and refuse to perform the procedure

regardless of the circumstances.” This seems an untenable position for a veterinarian providing end-of-life care when euthanasia is almost universally seen as an appropriate choice to minimize suffering in terminally ill animals. While the IAAHPC does recommend such veterinarians tell clients about their position before taking on a hospice care role and refer for euthanasia if a client wishes it, this seems an ethically dubious position.

The right of service providers of any kind, including healthcare workers, to refuse to provide services that are legal and ordinarily provided by people in their role as a result of their personal beliefs, including religious beliefs, has generally not been widely recognized as a legitimate right, nor has it been generally upheld by the courts. Personal beliefs don’t typically exempt one from performing the expected duties of one’s profession, so this seems a questionable exception to carve out for hospice veterinarians.

Much more worrisome, however, is the strong and consistent role of alternative medical therapies in educational and policy documents from the organized veterinary hospice community. The IAAHPC guidelines specifically endorse “integrative medicine” and the inclusion of alternative therapies in end-of-life care:

An integrative approach, using conventional and CAVM therapies, is recommended using the most appropriate interventions that control pain or other clinical signs. It is the recommendation of this Task Force that veterinary practitioners and animal hospice team members maintain current knowledge of the available treatment options for patients, whether these options are complementary or allopathic, and to choose therapies that are the most effective in treating the patient’s condition, most beneficial to the patient’s overall quality of life and have the fewest undesirable side effects.

Given the robust reasons to doubt the safety and effectiveness of most alternative therapies, this seems a perilous and irresponsible position to take. If a treatment doesn’t work, it provides no benefit to the patient, and integrating it into patient care cannot improve quality of life. Integrating it at the expense of scientific therapies, however, can certainly worsen patient care. As I discussed in my previous article, this appears to be the result of the fact that many of the leading figures in the animal hospice movement are also CAM providers. They have faith in CAM treatments regardless of the lack of evidence or even evidence against this belief, and as a result they assume the value of these therapies and promote them as a beneficial part of hospice care. Substituting personal belief and experience for scientific evidence is not the best way to protect patients, especially those as vulnerable as animals in hospice care.

There is, of course, limited and weak evidence for many veterinary therapies, conventional as well as alternative. And the area of pain control is especially difficult to generate strong, objective evidence in because the challenges in measuring pain and the effects of pain relieving treatments. Some CAM therapies fall into a grey zone where there is at least some plausible reason to think they may have benefits, or at least a level of evidence no worse than that available for conventional therapies. For example, though the evidence is not strong, there is some reason to think cold laser therapy (1,2), massage, and other kinds of physical medicine may have some benefits in terms of comfort, wound healing, and other issues relevant to hospice patients. Even acupuncture, if divorced from the nonsense of Traditional Chinese Medicine, might have some small beneficial effects, though the evidence is complex and uncertain.

Use of such methods, so long as it is not to the exclusion of science-based treatments, is not entirely unreasonable if measured claims are made and clients are given honest information about the limitations of the evidence. However, there are also CAM methods recommended by proponents of animal hospice that are clearly ineffective and can have no benefits at all. For example, a prominent and extreme proponent of veterinary homeopathy, Christine Chambreau (3,4,5), has lectured at the IAAHPC conference on the use of homeopathy in hospice patients.  As always, suggesting that homeopathy has any legitimate role in veterinary care ignores the overwhelming evidence that it is ineffective, and this is completely unethical. Substituting homeopathy for any real medical therapy is dangerous and wrong, and this should never be even tacitly endorsed by anyone interested in legitimate compassionate end-of-life care.

Similarly, the IAAHPC has had proponents of Reiki speak at their conference, and the organization even has a link to a pro-Reiki web site on their own web page. Reiki, of course, is a variety of “energy medicine,” which amounts to nothing more than a non-denomination variety of faith healing. It is fundamentally a spiritual practice, not only not proven to have any beneficial effects but outside the domain of science altogether since it is entirely faith-based. Offering it as part of hospice care not only promotes an unproven and unscientific practice as if it were a legitimate medical intervention, it blurs the distinction between the veterinarian as a healthcare provider and a spiritual counselor. This intrusion of personal spiritual beliefs into animal hospice is not in the best interests of patients or the hospice movement.

The IAAHPC does appear to view CAM not only as likely to be effective, but potentially as a substitute for some conventional therapies. For example, in the organization’s hospice guidelines, they state, “CAVM therapies may aid in reducing the required dosages of certain drugs.” And the usual misguided notion of scientific evidence as an optional “extra” rather than essential to evaluating the safety and effectiveness of our treatments appears in IAAHPC conference talks about the use of CAM in hospice care:

These therapies are safe, noninvasive, relatively inexpensive, and accessible… Their use can promote natural healing mechanisms… and also will create a sense of wellbeing in the patient. Serious and life-altering medical conditions…have been found to be responsive, to some degree, to the use of diet, nutraceuticals and botanicals and acupuncture.

Patients who are in terminal care may not have the time to wait for the completion of more studies validating the benefit of the concurrent use of complementary therapies… Each clinician needs to decide where they stand in terms of the degree of rigor of the evidence versus the benefit-potential that complementary therapy could provide their patients’ QoL. In the hospice-palliative care realm, using evidence-based measures is of paramount importance, as long as the patient doesn’t suffer as a result of the time spent in academic bickering over the level of quality of the evidence.

This sort of position assumes the efficacy and safety of methods when these are often not, in fact, well-demonstrated, and it assumes that it is somehow better for patients to be exposed to therapies with little to no evidence of safety and effectiveness and significant controversy about their effects than to test these therapies before using them. The normal process of scientific investigation, which has brought such tremendous and unprecedented health benefits to the all of us, is dismissed as “academic bickering,” and it is assumed that any objection to trusting anecdote as the basis for using CAM treatments is a mere pedantry. Such views place the well-being of patients at the mercy of the beliefs and opinions of individual veterinarians, even when these conflict with scientific evidence.

Bottom Line
I believe hospice care has the potential to make the end of life more comfortable and peaceful for many veterinary patients, and I think it is crucial that we do a better job as a profession of serving the needs of patients and their human caregivers at this challenging and emotional time in the cycle of life.  However, I think our clients and patients are especially vulnerable when coping with terminal illness and death, and we have a responsibility at this time, perhaps more than any other, to be sure the care we offer is the best, safest, and most effective possible. Science and scientific evidence offers the best tool available for evaluating the treatments we offer, and it has earned the special roles it plays as the primary means of identifying the risks and benefits of the treatments we employ.  While we must often make due with less than optimal evidence in making clinical decisions, we are ethically obligated to rely on science to the greatest extent possible in choosing therapies and counseling our clients.

Unfortunately, the organized animal hospice movement includes a relatively high proportion of veterinarians who are believers in unproven or even outright ineffective therapeutic practices, including acupuncture, herbal medicine, energy medicine, homeopathy, and others. Because of this representation, organizations and individuals promoting hospice care are often also promoting the misguided “integrative medicine” approach (c.f. 6, 7 for more  on this concept). This includes treating both promising but unproven treatments (such as low-level laser therapy), disproven treatments (such as homeopathy), and even fundamentally spiritual or religious practices (such as Reiki) as if they were the equivalent of science-based conventional medical interventions. This misleads clients and places patient welfare at risk.

While the IAAHPC does acknowledge that hospice therapies should be effective and, to the extent possible, evidence based, in general it leaves the evaluation of these therapies to the discretion of individual veterinarians and takes a very weak stance on how efficacy and evidence are to be judged. While I truly do admire and share the goals of the animal hospice movement, and I appreciate the sincerity and commitment of hospice veterinarians, including those who offer CAVM treatments, to the well-being of hospice patients, I am troubled by the views of the IAAHPC and individual hospice providers towards CAVM and evidence-based medicine.

There is abundant evidence that our perceptions of the efficacy of our therapies are unreliable and misleading, and that caregiver placebo effects readily fool us into thinking we are alleviating suffering in our pets and patients even when we are using ineffective treatments. Sadly, the majority of veterinarians, whether primarily conventional of CAM-oriented, do not seem to appreciate this. In the case of hospice patients and their owners, this attitude has significant potential to lead to unnecessary suffering or ineffective care since there is often a perception of “nothing to lose” at the end of life. However, the experience of dying can be made more uncomfortable than it need be when ineffective treatments are used, and it is imperative the as a community veterinarians are vigilant in minimizing the risk of this in animal hospice patients.


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Ignorance is not a Virtue

The focus of this blog is the relationship between science and medicine, with an emphasis on skepticism, not politics. However, larger cultural problems in our attitudes towards science and reason are relevant in that they impact how people perceive science and scientific evidence, and the choices they make as a result. I was sufficiently impressed by some of President Obama’s recent remarks during a commencement speech at Rutgers University that I want to reproduce them here. I think they are an insightful commentary on a pervasive and dangerous anti-intellectualism that bedevils not only our political system but our ability to make choices, as a society and as individuals, about matters connected to science and health.

Facts, evidence, reason, logic, an understanding of science—these are good things. (Applause.) These are qualities you want in people making policy. These are qualities you want to continue to cultivate in yourselves as citizens. (Applause.) That might seem obvious. (Laughter.) That’s why we honor Bill Moyers or Dr. Burnell.

We traditionally have valued those things. But if you were listening to today’s political debate, you might wonder where this strain of anti-intellectualism came from. (Applause.) So, Class of 2016, let me be as clear as I can be. In politics and in life, ignorance is not a virtue. (Applause.) It’s not cool to not know what you’re talking about. (Applause.) That’s not keeping it real, or telling it like it is. (Laughter.) That’s not challenging political correctness. That’s just not knowing what you’re talking about. (Applause.) And yet, we’ve become confused about this.

Look, our nation’s Founders—Franklin, Madison, Hamilton, Jefferson—they were born of the Enlightenment. They sought to escape superstition, and sectarianism, and tribalism, and no-nothingness. (Applause.) They believed in rational thought and experimentation, and the capacity of informed citizens to master our own fates. That is embedded in our constitutional design. That spirit informed our inventors and our explorers, the Edisons and the Wright Brothers, and the George Washington Carvers and the Grace Hoppers, and the Norman Borlaugs and the Steve Jobses. That’s what built this country.

And today, in every phone in one of your pockets—(laughter)—we have access to more information than at any time in human history, at a touch of a button. But, ironically, the flood of information hasn’t made us more discerning of the truth. In some ways, it’s just made us more confident in our ignorance. (Applause.) We assume whatever is on the web must be true. We search for sites that just reinforce our own predispositions. Opinions masquerade as facts. The wildest conspiracy theories are taken for gospel.

But when our leaders express a disdain for facts, when they’re not held accountable for repeating falsehoods and just making stuff up, while actual experts are dismissed as elitists, then we’ve got a problem. (Applause.)

You know, it’s interesting that if we get sick, we actually want to make sure the doctors have gone to medical school, they know what they’re talking about. (Applause.) If we get on a plane, we say we really want a pilot to be able to pilot the plane. (Laughter.)  And yet, in our public lives, we certainly think, “I don’t want somebody who’s done it before.”  (Laughter and applause.)  The rejection of facts, the rejection of reason and science—that is the path to decline. It calls to mind the words of Carl Sagan, who graduated high school here in New Jersey—(applause)—he said: “We can judge our progress by the courage of our questions and the depths of our answers, our willingness to embrace what is true rather than what feels good.”

A while back, you may have seen a United States senator trotted out a snowball during a floor speech in the middle of winter as “proof” that the world was not warming. (Laughter.) I mean, listen, climate change is not something subject to political spin. There is evidence. There are facts. We can see it happening right now. (Applause.) If we don’t act, if we don’t follow through on the progress we made in Paris, the progress we’ve been making here at home, your generation will feel the brunt of this catastrophe.

So it’s up to you to insist upon and shape an informed debate. Imagine if Benjamin Franklin had seen that senator with the snowball, what he would think. Imagine if your 5th grade science teacher had seen that. (Laughter.) He’d get a D. (Laughter.) And he’s a senator! (Laughter.)

Look, I’m not suggesting that cold analysis and hard data are ultimately more important in life than passion, or faith, or love, or loyalty. I am suggesting that those highest expressions of our humanity can only flourish when our economy functions well, and proposed budgets add up, and our environment is protected. And to accomplish those things, to make collective decisions on behalf of a common good, we have to use our heads. We have to agree that facts and evidence matter. And we got to hold our leaders and ourselves accountable to know what the heck they’re talking about. (Applause.)

He also touched on the issue of engagement with people and ideas with which one disagrees, another important and relevant issue:

If you disagree with somebody, bring them in—(applause)—and ask them tough questions.  Hold their feet to the fire.  Make them defend their positions.  (Applause.)  If somebody has got a bad or offensive idea, prove it wrong.  Engage it.  Debate it.  Stand up for what you believe in.  (Applause.)  Don’t be scared to take somebody on.  Don’t feel like you got to shut your ears off because you’re too fragile and somebody might offend your sensibilities.  Go at them if they’re not making any sense. Use your logic and reason and words.  And by doing so, you’ll strengthen your own position, and you’ll hone your arguments.  And maybe you’ll learn something and realize you don’t know everything.  And you may have a new understanding not only about what your opponents believe but maybe what you believe.  Either way, you win.

We need this perspective, in politics and everywhere else in our society, and it was inspiring to hear someone in the most prominent and visible public position articulate and defend it.

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Acupuncture Fails to Qualify as a Specialty Area in Veterinary Medicine due to Lack of Adequate Scientific Evidence

I have written extensively about acupuncture and the scientific evidence concerning it, even going so far as to complete a certification course in acupuncture myself. This extensive examination has convinced me that while there are a few effects of electrical nerve stimulation done under the umbrella of acupuncture that might be clinically useful, overall the evidence does not support acupuncture as a powerful, widely useful therapy. Most of the apparent responses seen in humans are likely due to placebo effects or mild non-specific reactions to the minor trauma of needling. Since acupuncture is pretty safe when done properly, it is not unreasonable to try needling with electrical stimulation in specific cases where all other conventional means have been used appropriately or there are no available therapies with better evidence, and as long as clients understand the lack of evidence to support significant objective effects.

I also think that the limited potential for benefits from needling are often swamped by the risks from the nonsense associated with some schools of thought in the acupuncture field, particularly the so-called Traditional Chinese Veterinary Medicine (TCVM) approach. Unlike the medical acupuncture model, which at least attempts to ground needling therapies in established anatomic and physiologic principles, TCVM is effectively a religious belief system that is inconsistent with science-based medicine, and as such it does more harm, in terms of inflicting unproven therapies and mystical diagnostic and treatment practices on patients, than it can do good even if a few needling practices have some clinical benefits.

Given this position, I agree with the recent decision of the American Veterinary Medical Association (AVMA), following the recommendation of the American Board of Veterinary Specialties (ABVS), to deny a petition by an association of acupuncturists, dominated by the TCVM approach, to certify acupuncture as a legitimate medical specialty in veterinary medicine. Such certification requires that the area designated as a specialty be a legitimate, scientific discipline, not simply that it be a complex collection of beliefs and practices accepted by adherents regardless of the scientific evidence. Homeopathy is not a medical specialty any more than shamanism or ritual sacrifice to Apollo are medical specialties, because it has failed to prove it can or does work through scientific testing. While some non-TCVM approaches to acupuncture are more plausible and compatible with science than homeopathy or TCVM, even these approaches have failed to generate the kind of robust, consistent body of positive research evidence needed to justify creating an entire medical specialty within the veterinary profession.

In addition, any specialty in acupuncture would almost certainly include the majority of veterinary acupuncturists who practice faith-based, TCVM acupuncture. This would mislead animal owners into believing that the body of knowledge mastered by these practitioners was scientifically valid and equivalent to that mastered by specialists in cardiology, internal medicine, oncology, and other recognized specialties. This is clearly untrue, and it is encouraging that even such a political organization as the AVMA, which has refused to condemn homeopathy in the past despite acknowledging it is ineffective.

Of course, this decision doesn’t prevent anyone from offering acupuncture treatment of any kind. It simply makes clear that acupuncture advocates have not been able to generate reasonable scientific proof for their claims despite decades of trying. The decision appropriately challenges the trend towards integrating alternative therapies into veterinary practice even when there is not good evidence for their safety or efficacy.

Posted in Acupuncture | 6 Comments

John Oliver Nails It! How the Media Misreports Science.

With his usual humor and also very clear, accurate explanations, John Oliver talks about how scientific research is misrepresented in the media, and how this not only misleads the public about important health issues but undermines confidence in science.



Posted in Humor | 3 Comments

Dogs are Still not Wolves: Human Feeding Practices Have Shaped the Dog Genome

I have written many times about the argument, often made to support raw meat feeding or other alternative dietary practices, that dogs are basically carnivores and that because they were derived from wolf ancestors their optimal diet should be as much like that of wild wolves as possible. (see links to previous posts)*

On one level, this argument is an example of the Appeal to Nature Fallacy, which says that anything arbitrarily defined as “natural” must be benign or beneficial. In the case of diets for carnivores, this ignores the obvious facts that: carnivores in the wild don’t eat an optimal diet, they eat whatever they can catch or scavenge; malnutrition, parasites, broken teeth, and other harmful consequences of a “natural” diet are ubiquitous in wild carnivores; captive carnivores, protected from these and other hazards often live longer, healthier lives than their wild counterparts.

However, the “dogs are wolves and should eat like wolves” argument fails on another level, which is that dogs simply are not wolves. That should be obvious to anyone who tries to imagine a pack of pugs taking down and savaging an elk. But even on less obvious and dramatic criteria, the distinctions between dogs and wolves wrought by domestication. As I have discussed previously, changes in dentition, the GI tract, and the production of digestive specific enzymes illustrate the effects of artificial selection on the ability of domestic dogs to make use of a much wider range of food sources than wolves. A recent study has further explore the genetic changes behind increased production of amylase, an enzyme for digesting starch, that have accompanied initial domestication and subsequent selective breeding by humans.

Reiter T, Jagoda E, Capellini TD (2016) Dietary Variation and Evolution of Gene Copy Number among Dog Breeds. PLoS ONE 11(2): e0148899. doi:10.1371/journal.pone.0148899

As the authors explain,

Over time, and via cohabitation, the canine diet has been transformed from the carnivorous diet of its ancestor, the wolf, to a diet more closely matching that of omnivorous humans…This transformation increased variation in the domesticated dog’s diet, potentiating impact on numerous biological pathways.

Because humans populated a variety of habitats with different dietary staples, dog breeds from different places also consumed diets composed of unique combinations of food items. For many breeds, dietary changes resulted in increases in novel food constituents that may have required new, better, or more digestive mechanisms, thereby exerting differential selective forces on dogs living among different groups of humans. For example, starch digestion presented a new dietary challenge to which the dog likely adapted through alteration of three key genes in the starch digestion pathway

The study investigated the gene for amylase, and several other genes, and found that not only did the dog begin to produce significantly more amylase than the wolf after initial domestication, but that specific breeds of dogs produce different amounts based on the amount of starch in the diet of humans in the areas where those breeds were developed. In other words, changes in the nutritional needs of dogs have continued beyond initial domestication, showing the powerful impact of intensive selection, and these changes have been driven by what is eaten by humans particular breeds live with, reinforcing that until recently dogs have been shaped by human activity to adjust to our diet.

Consistent with studies with more limited datasets, we found that AMY2B CNV did vary with dietary starch intake. Dogs with high-starch diets…had a statistically significant higher mean CNV…compared to dogs with low-starch diets….

These findings expand upon the recent study of Axelsson and colleagues [ref in original], which found that AMY2B copy number is substantially increased in domestic dogs relative to wolves. This study presents evidence that in dog breeds that were exposed to starch-rich diets, positive selection continued to influence AMY2B copy number after this initial copy number expansion.

The information from this single paper does not, of course, tell us much about the optimal diet for dogs generally nor for any particular breed. It simply illustrates that human activity, including what we eat and, consequently, what our dogs eat, has shaped our dogs genetically and functionally as well as in the obvious anatomical ways. Dogs are not wolves, and their dietary needs are much more a function of what humans have historically fed them than of what carnivores in the wild eat.


* Raw Meat and Bones for Dogs: It’s Enough to Make You BARF

Repeat After Me: “Dogs are not Wolves”

One More Time: Dogs are not Wolves!

Posted in Nutrition | 3 Comments

Teaching Integrative Medicine in Veterinary Schools: Part of an Evidence-Based Curriculum or Trojan Horse for Alternative Medicine?

I recently came across an interesting paper that cited some of my previous writing about the relationship between evidence-based medicine and alternative medicine.

M.A. Memon, J. Shmalberg, H.S. Adair III, S. Allweiler, J.N. et al. Integrative veterinary medical education and consensus guidelines for an integrative veterinary medicine curriculum within veterinary colleges. Open Veterinary Journal, (2016), Vol. 6(1): 44-56.

This article presents an argument for how and why alternative therapies should be taught in veterinary schools under the heading of Integrative Medicine. This argument contains a number of reasonable points and also a number of significant flaws. I’ll begin with the points of agreement between my view and that of the authors.

Where I Agree
The paper starts by arguing that because many CAM therapies are sought by animal owners and have a certain degree of popularity, veterinarians are likely to encounter them. While the authors cite some specific numbers about the popularity for alternative therapies that are a bit misleading, there is no doubt that most vets will regularly encounter questions about alternative therapies from clients. Since one of the most important roles for a veterinarian is as an educator helping clients make fully-informed decisions about the care of their animals, it is necessary for vets to be knowledgeable about those CAM therapies clients may seek or already be using.

Of course, the most appropriate response to clients questions about such methods is often to explain the lack of plausibility and supporting evidence behind the practice and discourage its use. And if vet students are to be taught about CAM, the controversial issue, of course, is precisely what they should be taught about these practices. That will be addressed shortly, but in any case, vets do need to understand the claims made about CAM therapies and the evidence available regarding them, and having some formal introduction to this subject in veterinary school makes sense.

Another point on which the authors and I agree is that such instruction about CAM practices should not be provided or funded by organizations with a primary mission of promoting or teaching CAM. I have discussed previously the role of the AHVMA and AHVMF, the Chi Institute, and other CAM training and advocacy groups in promoting alternative therapies, often blatantly disregarding or misusing scientific evidence to further their agenda. Any involvement of such groups in teaching CAM would introduce a severe risk of bias and likely make such training more a marketing exercise rather than a legitimate, evidence-based means of preparing vets to answer client questions about CAM.

While I agree with the authors about the importance of minimizing the risk of bias in the teaching of CAM in veterinary schools, I am not convinced that this can be readily achieved. This article, for example, was itself a product of an effort initiated and conducted in association with the American Academy of Veterinary Acupuncture, so it already involves exactly the kind of support from a group advocating for a particular CAM therapy which the authors are acknowledging can introduce bias into the teaching of CAM. In addition, a number of the lead authors are also instructors at the Chi Institute, members of the AHVMA, and otherwise affiliated with CAM advocacy groups that have a clear bias with regard to the safety and efficacy of alternative therapies.

And as I have discussed before, the very question of expertise in CAM raises the issue of potential bias. Almost no one pursues advanced training or certification in an alternative medicine practice unless they are irrevocably committed to a belief in its value to patients. However, in the case of some such therapies, there is substantial reason to doubt whether the principles or practices for which such expertise is defined have any reality at all. Being an expert in homeopathy, for example, is a bit like being a Catholic priest. The expert undoubtedly has extensive knowledge about the relevant subject matter. But by itself, this knowledge doesn’t demonstrate the objective reality or truth of this subject matter to those outside of the belief system, and such expertise is of little value to those who are not already believers.

If only CAM “experts” are involved in teaching CAM to veterinary students, the content of this education is going to necessarily be rooted in beliefs about the underlying truth of the matter regarding these therapies which are not widely accepted by scientists and conventional healthcare providers. Even if an effort is made to include some skeptical input into these courses, it will be difficult to find outsiders who have put the time and effort into investigated the claims of CAM advocates and understand their theoretical and evidentiary limitations.

The inclusion of such skeptics, when they can be found, doesn’t entirely solve the bias problem in any case. This potentially sets up the presentation of CAM as merely a difference of opinion among scientists or clinicians. This may be true for some CAM practices, but for others (homeopathy being, again, the classic example) there really is no substantive difference of opinion among scientists, simply a consensus based on evidence which a small group of true believers refuse to acknowledge.

So while the ideal of a course which teaches vets what they need to know to effectively answer client questions and provide guidance about CAM in an objective, evidence-based way is laudable, in practice it seems very difficult to achieve. In fact, the very premise of his article, that there is benefit to patients in a strategy which integrates the disparate domains of conventional and alternative medicine, is debatable, as I will discuss shortly.

Finally, there are a number of other points on which I agree with the authors of this article. They are clear that any discussions of CAM with students should emphasize relevant research evidence appraised critically rather than simply personal or anecdotal experience, historical traditions, etc. The limitations of such evidence should be explicitly presented, the critical issue of placebo effects should be addressed, potential risks as well as potential benefits should be communicated, and CAM therapies should not be presented as replacements for established conventional treatments. I also agree with the authors that many conventional medical practices lack strong supporting research evidence, and it can be appropriate to consider alternative therapies that have the same level of basic plausibility and limited supporting evidence as such conventional treatments when the urgency of intervening justifies the uncertainty about the effects of doing so.

Where I Disagree
There are also, however, many points on which I would disagree with the authors of this article. Perhaps the most obvious is the merits of the very concept of Integrative Medicine. If we can demonstrate a particular therapy is safe and effective using appropriate scientific testing, why does it require a separate category, whether we label it “alternative or “integrative,” to be utilized as part of our overall treatment approach? If we test a therapy, show it works, and begin using, how is it not simply another tool of conventional or science-based medicine?

Tim Minchin has most eloquently delineated the real meaning of terms such as complementary and alternative:

By definition…complementary and alternative medicine…have either not been proved to work or been proved not to work. Do you know what they call alternative medicine that’s been proved to work? Medicine.

Or, perhaps less poetic but still to the point, as Dr. Marcia Angell has put it:

There cannot be two kinds of medicine — conventional and alternative. There is only medicine that has been adequately tested and medicine that has not, medicine that works and medicine that may or may not work. Once a treatment has been tested rigorously, it no longer matters whether it was considered alternative at the outset. If it is found to be reasonably safe and effective, it will be accepted.

The concept of integrative medicine requires that we combine therapies that are in some sense viewed separate but equal. But what is the nature of this difference? The usual differences that turn out to justify this separateness include: a theoretical foundation that is incompatible with established scientific knowledge; a lack of supporting scientific evidence; or a committed group of supporters who believe a therapy is safe and effective based on anecdotal experience or historical and cultural tradition despite the absence of supporting scientific evidence.

There is no reason to integrate a plausible and scientifically proven therapy into mainstream medicine but preserve for it a separate identity as “alternative.” If we treat all proposed therapies equally, evaluating their mechanisms and clinical effects at every level through rigorous research, then we can simply accept those that prove their value and abandon the rest. The only use for a special category of Integrative Medicine is to present some therapies as equal in legitimacy to conventional treatments before they have been properly tested and proven their worth.

Another problem with the concept of Integrative Medicine is that it is arbitrary in which practices it encompasses. Since most of the authors of this paper practice acupuncture, of course that is included in their suggested course material. Botanical or herbal medicine is also included, and one could claim this is justified since this is one of the most popular CAM practices. However, dietary supplements are arguably even more widely used, and they aren’t mentioned in this category or under “integrative nutrition.” Are these an alternative therapy to be integrated, based on scientific evidence, with conventional treatments? They are usually marketed as such by CAM practitioners. Or, if such supplements are shown to be safe and effective for particular conditions, are they simply yet another element of scientific medicine? My use of fish oils for atopic dermatitis and arthritis isn’t practicing “integrative medicine.” It is just making use of a nutritional intervention with reasonable plausibility and supporting research evidence in the usual course of scientific medicine.

Similarly, the authors identify Physical Rehabilitation as a key content category for an integrative medicine course. While there is a disappointing lack of research in this area involving veterinary patients, physical therapy is an established, ordinary part of conventional human medicine. There is no reason to create a special category to teach this in an evidence-based way to veterinary students. It should be included in the curriculum just like any other mainstream medical practice.

On the other hand, the authors suggest that the philosophical and theoretical principles of TCM and homeopathy should be taught as part of integrative medicine despite being completely inconsistent with the principles and established knowledge of basic science. The authors take something of a “teach the controversy” approach similar to that used by creationists.

The argument is that we should teach the different points of view and let students make up their own minds. Of course, this is nonsense when the context is the explicit education of students in science and science-based medicine. There is no controversy about biological evolution in science, so no need to teach religious or philosophical alternatives in the science classroom, though these may be worth studying in the domains of religion, history, cultural studies, and psychology. Likewise, there is no scientific controversy about potentization by dilution and succession or the role of Excess Wind in generating disease. These are religious and philosophical ideas which have no place in the science classroom.

If the authors believe it worthwhile to expose veterinary students to pseudoscientific or anti-science views of health and disease for the purpose of preparing them to refute these when asked about them by clients, there might be some merit to that idea. However, this needs to be done with the explicit and clear intent of inoculating students against such ideas. And the course material should then include energy medicine, Bach flower essences, Reiki, intercessory prayer, and other widely available faith-based health practices. However, the authors do not suggest that a major focus of the course should be preparing veterinarians to refute or discourage alternative medicine practices. The exclusion of some unscientific philosophical views and inclusion of others in the suggested curriculum seems to be mostly a feature of the authors’ own views of what is clinically useful. Once again, bias proves slippery and difficult to eliminate from a course on CAM approaches.

The reluctance to explicitly refute any CAM practice, regardless of the evidence, is a consistent problem in alternative veterinary medicine, though conventional vets sometimes seem just as unwilling to reject implausible or disproven CAM practices and CAM vets. Unfortunately, science works primarily not by validating but by rejecting hypotheses. The key to its effectiveness is that our biases tend to lead us to confirm our existing beliefs, and the tools of science that limit the misleading effects of these biases tend to help us reject our hypotheses when they are mistaken. While scientific research is often seen as primarily useful for confirming what we already think we know, this is actually not how it works best.

There is almost no hint in this article of the important role of any course addressing CAM in discouraging therapies that are clearly incompatible with science or have been shown pretty reliably not to be effective. How can we teach vets to respond effectively to client questions about healthcare practices if we are unwilling to ever acknowledge that some are ineffective or harmful and should be discouraged?

These authors represent a group of veterinarians with legitimate expertise in scientific medicine, and they have produced a thoughtful and interesting document. While I agree with a number of their key points, I think it is a bit misleading to call this a “consensus guideline.” It is only the consensus among individuals with a pre-existing belief in the premises of their own argument. All the authors believe acupuncture is a useful therapy, though that is not something one can reasonable call established by good science. Many believe more generally in the value of Traditional Chinese Medicine as a method for evaluating disease and choosing therapies, despite the deep incompatibility of this faith-based folk system of metaphors and the principles, methods, and knowledge base of science. And all the authors believe in the concept of Integrative Medicine as a useful schema for evaluating alternative therapies and integrating them into mainstream clinical practice. All of these beliefs are controversial and outside the mainstream scientific view.

Ultimately, the type of curriculum proposed here would almost certainly function as a Trojan horse for alternative therapies. CAM practices would be treated as different but equal to conventional practices, and this would create the impression that they can be reasonable accepted and employed regardless of the plausibility of their underlying mechanism or the evidence for their clinical effects. Though the authors claim to agree with my assertions elsewhere that all potential interventions should be assessed by the same, soundly scientific standards, they have advocated the concept of integrative medicine, which ultimately fails to accomplished that. Rigorous testing of individual interventions and acceptance or rejection on their merits does not require that some practices be viewed as special and be “integrated” with conventional medicine. These practices should, if they prove their worth, simply be “medicine,” and they should be taught as such.

I do still agree with the authors that some attention to CAM should be paid in the veterinary school curriculum in order to prepare students to answer questions and guide clients in the use or rejection of these practices. The best way to accomplish that, however, isn’t clear. I personally think an explicit course in Integrative Medicine will inevitably have an inherent bias towards promoting CAM practices as equivalent to conventional interventions regardless of the quality of evidence or the compatibility of the basic theory with established science. It might be better to have a section in a broader course about Evidence-Based Medicine which is devoted to Evaluating Unconventional Therapies. Such a section could illustrate the application of EBM methods to the panoply of CAM practices, from the plausible and well-studied to the disproven or inherently unscientific and faith-based. Students would learn about these approaches in a way that emphasized the need for a consistent, science-based approach to evaluating all potential interventions, rather than the perspective of seeking out CAM therapies to be integrated into clinical practice based on anecdote first and then scientifically evaluated later all while maintaining a distinct ideological identity as “integrative.”

This approach would best serve the needs of both vets and animal owners. Vets would get a better, more thorough instruction in how to use science most effectively to make decisions and recommendations about all possible interventions, and all ideas would be treated equally and fairly and judged by the same epistemological standards. The fundamentally ideological categories of CAM and Integrative Medicine would be unnecessary. Those practices that prove their value through the usual route of scientific investigation would simply be “medicine,” and those that did not would simply be unproven or failed hypotheses, not entitled to special treatment simply because of the faith some vets or owners have in them or their historical origins.



Posted in General | 3 Comments

Clinical Reasoning

One subject I am especially interested in is the ways our inherent reasoning processes can lead us to develop and defend mistaken beliefs. Many features of human observation and thought have evolved for quick judgments and efficient approximations under conditions of limited information. The disadvantages of these heuristics is that they are more susceptible to bias and some kinds of error than careful, formal reasoning processes. As veterinarians,  the conclusions we make about our patients and our own treatments are subject to all the same sources of error that bedevil all human thinking.

I have written before about cognitive bias and clinical decision making in veterinary medicine. Now a new series of articles in the Journal of Feline Medicine and Surgery has taken on the subject of clinical reasoning and cognitive bias. This entertaining and informative series should be a valuable resource for veterinarians but also for pet owners interested in how decisions are made in the care of their pet. Some of the articles are freely available, though not all are yet.

Think about how you think about cases

Intuitive and Analytical Systems

Managing Cognitive Error

Use of Heuristics and Illness Scripts- not yet published

Posted in Science-Based Veterinary Medicine | 1 Comment