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.

Posted in General | 3 Comments

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

SkeptVet Talking about Alternative Medicine for Pets on the Prism Podcast

Had a great time chatting about alternative veterinary medicine on the Prism Podcast. You can download the mp3 below if you like or listen on the web or on iTunes.


Posted in Presentations, Lectures, Publications & Interviews | 7 Comments

SkeptVet’s Acupuncture Adventure- The Hand’s On Training and Wrap-Up

After nearly 100 hours on online instruction and independent study, my acupuncture training has concluded with a 5-day hands-on practicum and both a written and practical exam. All that remains to do to finish my certification in Veterinary Medical Acupuncture is a brief case report. This seems, then, like a good opportunity to wrap up SkeptVet’s Acupuncture Adventure and see what, if anything, has changed in my views and understanding of acupuncture as a result of this process.

Clinical Intensive Portion of the Acupuncture Course
I will begin by sharing my experience in the practical training portion of the course. Many folks who know my skeptical and science-based views have asked if I met a lot of strange people or dedicated adherents to pseudoscience in this course, but that really wasn’t the case. For one thing, this particular course is heavily marketed as science-based and an alternative to the TCVM approach to acupuncture, so it tends to attract a more mainstream set of students. And it is important to remember that despite the significant limitations and problems in the acupuncture literature, it is pretty widely accepted in the medical community as having at least a few legitimate benefits. While I’m still not completely convinced this is true when one looks into the literature deeply and critically, I recognize that many vets and MDs who are genuinely science-based in their views and practices view acupuncture as perfectly consistent with that approach when it doesn’t involve too much talk of Qi and other TCM metaphors.

I also think we have to be wary of the natural human tendency, as strong among skeptics as those who believe in alternative medicine, to stereotype and caricature people who disagree with us. While there are interesting trends and correlations to investigate between temperament and a variety of views and beliefs, the world is not neatly and rigidly divided into the skeptical and the credulous. I have always emphasized that even believers in the most egregious nonsense, such as homeopathy, often turn out to be as intelligent and reasonable on a day-to-day level as the most committed skeptic. Perhaps the greatest challenge to skepticism and rationalism is the fact that the road to irrational or pseudoscientific beliefs is paved with many normal, ubiquitous humans cognitive features we all share. It would be easier to mitigate the dangers of pseudoscience if only the stupid or the gullible believed in it, but that isn’t reality.

As a skeptic, I am routinely assumed to be negative, argumentative, cynical, closed-minded, and generally unpleasant by people who know nothing of me other than my views on alternative medicine. This is unfair and inaccurate, but it is no more unfair or inaccurate than assuming anyone who might be interested in learning acupuncture must be gullible or some kind of caricature of a New Age hippy.

Generalizations are sometimes useful and interesting, but they are also a hair’s breadth away from the kind of stereotyping that impedes accurate understanding. For those of you who haven’t seen it yet, here is Tim Minchin offer some thoughts that strike me as relevant to this issue.

For the most part, the students and instructors I talked to in this course seemed drawn to acupuncture for fairly typical reasons. Some simply felt frustrated by the lack of validated therapies for many important clinical problems and felt that exploring something new might be worthwhile. Given the poor quality research evidence for much of conventional veterinary practice, the lack of strong scientific evidence for acupuncture didn’t necessarily seem to be a deterrent for most.

And of course, I heard a lot of stories about personal experiences that had drawn participants to acupuncture. As always, in conventional medicine nearly as much as alternative medicine, anecdote is king. Some students had experienced improvement after receiving acupuncture treatment themselves for medical problems that had been persistent or otherwise recalcitrant to treatment. Others had seen patient who were very ill, had poorly understood conditions, or had been expected not to recover improve dramatically after acupuncture treatment. Almost everybody had some experience with acupuncture, laser, massage, or some other kindred practice that they felt was of benefit to them.

These experiences naturally create a very compelling sense that the improvement must be due to the therapy, despite all the reasons why this may not be true, and the long history of the failure of anecdote-based medicine. And there is an equally natural and unfortunate tendency for one such experience to lead people to be more accepting in general of anecdotes as evidence, even for the more implausible treatments. Many prominent advocates of alternative practices describe such “conversion” experiences as the start of their CAM careers. There is sometimes a sense that if one claim for an alternative therapy turns out to be true (or at least seems to), then they must all be taken seriously. Obviously, this is fallacious reasoning, and each claim and modality has to be evaluated independently regardless of whether it carries some vague and often misleading label as “integrative” or “Western” or something else.

Unfortunately, very few vets have the time, training, or inclination to critically appraise the scientific literature when investigating therapies that are new to them. And sadly, the limitations in the veterinary literature (and the scientific literature generally) make much of it less reliable a guide to what works and what doesn’t than we might wish. This only strengthens our reliance on personal experience and anecdote.

This is, again, a natural and universal aspect of human reasoning. But while anecdotes provide both a wonderful source of testable hypotheses and at least a somewhat rational basis for specific practices pending the development of better evidence, they are, of course, a deeply unreliable basis for medical practice.

Much of veterinary medicine, again conventional as well as alternative, is largely anecdote based, and we have to live with this in the absence of better quality evidence. But this requires a solid understanding of why we should have only very weak confidence in practices that have not been scientifically validated, regardless of our own apparently miraculous personal and clinical experiences. Unfortunately, we do a very poor job of providing veterinarians with this understanding during their training. The students and instructors in this course were, in general, no less critical in their thinking and no more susceptible to the allure of anecdote and personal experience than those I meet in purely conventional practice.

The practical training itself struck me as a mixed bag. There was a strong emphasis on familiarity with anatomy, which is always a worthwhile way of approaching the physical exam. I found this a useful refresher, given I am 15 years out of school and haven’t formally studied anatomy in a long while. And I felt like the folks doing physical therapy and rehabilitation had a lot of useful insights into evaluating patients with musculoskeletal problems. While there is little data on physical therapy interventions in veterinary medicine, this is a well-established and useful dimension of human medicine, and it is highly likely it will be a useful addition to companion animal medicine, though as always the research identifying which practices are useful for which conditions and all the other important details will lag well behind clinical implementation of these practices.

There was a heavy emphasis on myofascial trigger points as a focus of diagnosis and treatment. I have discussed this topic before. The subjective nature of this phenomenon was very apparent, as different students and instructors often disagreed about the location and significance of MTrPs they felt they detected. In some patients, areas of muscle tension with repeatable behavioral responses to palpation did seem pretty obvious. But in other cases, confident claims about MTrP detection were made based on pretty weak behavioral responses and with great inconsistency in the opinions of different individuals examining the same patient.

As an example, one instructor was adamant about a MTrP being present at a specific spot on one dog. I could not appreciate this myself on palpation. As I was palpating, she noted the dog flick its ear and declared that as proof I had found the point. However, she couldn’t see from her position that the ear twitch occurred when I had accidently brushed that ear with my other arm, and I suspect the twitch was just a reaction to that mild direct irritation of the ear. This doesn’t mean there wasn’t a MTrP that the instructor could feel and I couldn’t, of course. But it does illustrate the problem of subjectivity and confirmation bias in MTrP theory.

While I am still agnostic about the MTrP as a clinical entity, I am concerned that with the strong element of subjectivity in its detection it seems a less than totally reliable concept upon which to base physical medicine interventions. That said, once again such subjectivity is ubiquitous in veterinary medicine, and the detection of pain, nausea, anxiety and many other clinically important variables are no less subjective than the detection of MTrP, so that alone isn’t sufficient reason to reject the concept.

The portions of the training specifically devoted to needling were interesting and also a mixed bag. The research evidence used to justify needling was mostly covered in the online portions of the course, so there wasn’t much discussion of that in the practical training. Some instructors were careful to make only relatively measured and limited claims for acupuncture, acknowledging that the evidence is complex, limited in significant ways, and generally not definitive. On the other hand, almost everyone had a quite obvious personal conviction that acupuncture was highly effective based on their clinical experiences. As I’ve already discussed, this is a ubiquitous and natural, but also deeply problematic, element of both alternative and conventional veterinary medicine.

I do think this type of course, ostensibly treating acupuncture the same as any other therapy in terms of striving for a plausible physiologic rationale and recognizing the need for pre-clinical and clinical research validation, is less faith-based than the sort of course provided by the Chi Institute and other TCVM organizations. There is at least some recognition that much of the practices being taught are not supported by high-level or high-quality evidence and that this is less than ideal. However, anecdote and personal experience remain sufficient in the minds of most of the practitioners, and what evidence there is tends to be interpreted in the most positive possible way. Negative studies are consistently dismissed due to methodological limitations, while positive studies are much more readily accepted as valid, and the general paucity of good evidence in veterinary medicine is seen as tacitly justifying the use of acupuncture despite the weakness of the science behind it.

On a practical level, I did find the application of needling to the many animals used in the practical training somewhat reassuring. Virtually none of the animals manifested any obvious anxiety or discomfort about their treatment. A variety of distractions were used, mostly food related, however many of the animals (mostly owned by the instructors or their clients) were quite comfortable and relaxed during treatment, even by inexperienced students, with no need for distraction at all.

In general, the needles used are extremely small (0.1-0.25mm diameter), and certainly far smaller than those I use routinely for blood and urine sampling, aspiration of masses and internal organs, and many other routine conventional procedures. I had a number of opportunities to needle myself or be needled by others, and while I didn’t experience any of the physical or emotional sensations often described as evidence of the powerful effects of acupuncture, I also didn’t find it particularly uncomfortable. Even the electrical nerve and muscle stimulation I experienced was pretty benign at the usually recommended levels of intensity.

Given that the evidence for benefits from acupuncture is poor, I think it is important that we not expose patients to significant discomfort or risk if we are going to try it for conditions that have no validated treatment. The instructors were all very cautious about causing any discomfort and very clear about the need to avoid reported complications, such as puncturing body cavities or vital structures. Such complications are reported for acupuncture, and some of the instructors had personal experience with them. However, even reviews of the literature by skeptics show that such complications are rare and usually associated with failure to follow standard safety recommendations or the result of needling done by improperly trained practitioners. So while the training didn’t add much in terms of evidence for the efficacy of acupuncture, it was reassuring in terms of reaffirming that the risk and discomfort associated with the practice are minimal.

View on Acupuncture from Start to Finish
At the beginning of this course, I summarized my starting views of acupuncture. In brief, my conclusions were these:

My current view is that while needling undoubtedly has physiological effects, it has not been convincingly demonstrated that these are predictable, repeatable, and controllable to achieve beneficial clinical outcomes. I also am not convinced that acupuncture points or channels exist as a consistent network of identifiable anatomical structures that can be predictably identified and manipulated to achieve a desired clinical goal.

Ultimately, much of the acupuncture literature cannot be viewed as very reliable due…[various] sources of bias. The best controlled studies seem to suggest that acupuncture affects subjective symptoms and perceptions more than objectively measurable indicators of disease. This is most consistent with a placebo effect, and perhaps some very non-specific physiologic effects. However, there is some room for rational uncertainty about the extent to which acupuncture might have small benefits in terms of pain, nausea, and a couple of other clinical symptoms.

There are definitely risks associated with acupuncture…Infections and injuries from needles, sometimes serious, have been reported. Overall, serious adverse effects seem to be quite rare when experienced, formally trained acupuncturists are doing the needling.

Not much in these conclusions has changed as a result of taking this course. I have had an opportunity to review the experimental literature at length. There are a few studies, almost all involving electrical stimulation of peripheral nerves, that are pretty convincing in terms of showing objective physiologic effects of needling that might have clinical relevance. However, as yet there are few veterinary studies that control for bias well enough to allow any firm conclusion about whether these potential benefits can actually be consistently realized in clinical patients.

David Gorski has described electroacupuncture as a “bait-and-switch” with electrical nerve stimulation as an example of the “bait,” a potentially real intervention labeled in such a way as to appear to validate a much larger, and less plausible collection of concepts and claims. I think there is some legitimacy to this argument. If some traditional acupuncture points fall close to peripheral nerves or other anatomic structures we might reasonably want to use as targets for medical treatment, this doesn’t show that the overall pattern of channels and points used, even if acupuncturists could agree on only one, is a rational or scientific schema. And even if electrical stimulation of specific nerves using needles, or potentially needling in some locations without electrical stimulation, turns out to have consistent and objective clinical effects, this doesn’t make any and all claims made for acupuncture plausible or sound any more than the efficacy of one antibiotic for one type of infection validates the use of all antibiotics or even all drugs. Specific interventions need to be evaluated individually.

That said, I also think that if there is some “bait” in acupuncture, some objectively measurable effects of needling with or without electrical stimulation, it is worthwhile taking this seriously even if it is “tainted” to some degree by association with TCM or other pseudoscientific acupuncture practices. If one throws out the mystical energy medicine nonsense, pulse and tongue diagnosis, and all the religious and philosophical trappings of TCM, there remains a degree of plausibility to the idea that some needling and electrical stimulation interventions, labelled as “acupuncture” or by some other name, may be useful. The evidence for this in veterinary medicine, at all levels from pre-clinical to clinical trial, is poor but no worse than for a surprising number of conventional interventions.

Skepticism requires a careful, critical, nuanced evaluation of claims, relying on scientific evidence where possible and proportioning confidence in our conclusions to the strength of the evidence. At the beginning of this course, I had a pretty low level of confidence that acupuncture has meaningful clinical benefits, and that is still true. But I began with the belief that “there is some room for rational uncertainty about the extent to which acupuncture might have small benefits in terms of pain, nausea, and a couple of other clinical symptoms,” and that remains true as well. A detailed review of the evidence presented in the course leads me to believe that acupuncture is generally safe, probably objectively neutral with some placebo and other mild non-specific effects in most cases, and potentially truly beneficial in a few applications, especially those involving subcutaneous electrical stimulation of peripheral nerves.

What’s Next?
So what does this lead to in terms of my clinical practice? I have mentioned before that I am considering offering some kinds of needling or electrical stimulation practices under the rubric of “acupuncture.” My reasons for this include: 1) the small, but not non-existent, potential for clinical benefits; 2) the lack of better-validated treatments for many important clinical problems where pre-clinical research suggests needling might be useful; 3) the low risk; and 4) the desire to avoid seeing clients fall into the hands of TCVM vets or other practitioners they are currently being referred to for acupuncture and who consistently undermine their use of science-based therapies.

Some readers have expressed concern about my potentially offering acupuncture treatments to patients. This concern appears to be founded in a number of particular objections.

Some have a strong confidence that no version of what is often called “acupuncture” can possibly have any clinical benefits, so any use of it would be unjustified. I have already addressed this in my detailed analysis of the evidence concerning specific acupuncture practices. While my confidence in the potential benefits of most specific needling practices is low, it is not zero for all of them, as it appears to be for these readers.

It is, of course, a philosophical issue whether or not it is ethical to offer treatments with only weak supporting evidence, and under what circumstances such might be legitimate to try. My own feeling is that when a practice has at least some evidence of plausibility (it could work), and perhaps even some weak evidence of clinical effects (it might work), even if it doesn’t have strong supporting clinical trial evidence to show it does work, it can be acceptable to offer such a therapy. One condition for doing so, in my opinion, is that any claims made must be proportional to the evidence, so clients need to be told that the hoped-for benefits are speculative. And if the benefits are uncertain, the risk and discomfort associated with the practice must be minimal, and it must not be used as a substitute for any better-supported treatment. I do think there are a few circumstances in which acupuncture can be justified under these conditions.

Other readers have suggested that needling animals is “torture” due to the discomfort it causes in patients who can’t give their own consent for the experience. Again, while I believe we must tolerate very little in the way of risk and discomfort when our confidence in the benefits of our therapies is low, my belief is that acupuncture is very unlikely to cause injury or pain, certainly less so than any other conventional practices I use routinely and which also have limited and weak evidence of benefit.

My own biggest concern about potentially offering acupuncture is the problem with distinguishing the many and incompatible associations of the term. Given it is pretty safe, needling of muscles and electrical stimulation of peripheral nerves strike me as reasonable interventions when used for specific indications that have some supporting evidence (e.g. pain, vomiting, GI motility disorders, etc.), when there are no better validated interventions available, and when owners are clearly and honestly informed about the lack of strong evidence. However, just as suggesting this may strike some skeptics as evidence that I have “drunk the Kool-Aid” that is TCVM acupuncture, so it may strike some pet owners as an endorsement for all the varied claims and practices labeled “acupuncture,” including those which I think are utter nonsense.

Distinctions between acupuncture as a form of “percutaneous electrical nerve stimulation” versus a means of “tonifying Yang” and “moving Wind” are meaningful but likely to be lost on many lay people. I share the concerns others have raised that even if I stick with the few plausible needling practices and am very careful about limiting my claims and explaining my rationale, I could still be misinterpreted as supporting a range of claims and myths associated with acupuncture which I actually see as pseudoscience.

A popular metaphor for “integrative medicine”, which I have quoted many times, comes from Mark Crislip. He has said, “If you integrate fantasy with reality, you do not instantiate reality. If you mix cow pie with apple pie, it does not make the cow pie taste better; it makes the apple pie worse.” In the course of digging through the claims and evidence concerning acupuncture, I have come up with a related simile that fits my feelings about this topic a bit better.

I believe that the few potentially beneficial practices in the acupuncture collection are like ponies buried under a large pile of horse manure. The trick is to dig the ponies out and put them to work without getting thoroughly covered in manure. I’m not sure exactly how to go about this, but I also feel obliged to not ignore even the limited potential for benefit to patients in those cases where there is some reason to think needling and electrical stimulation might be helpful and better-validated options have failed or don’t exist.

Since I think these are interesting and important issues, for veterinarians and pet owners, I will continue to share my thoughts and experiences about them here. I welcome questions and comments from both “sides” of the issue, though as always I prefer substantive and civil input. Thanks for coming along on SkeptVet’s Acupuncture Adventure!



Posted in Acupuncture | 8 Comments

Evidence Update- Cranberry Extracts and Urinary Tract Infections in Dogs

I’ve written in the past about the subject of cranberry extracts used to prevent or treat urinary tract infections. (1, 2) There is some in vitro and lab animal research that suggests these products might reduce the ability of a limited set of bacteria (fimbriated E. coli) to stick to the lining of the urinary tract, and might thus have some value in preventing, though not treating, urinary tract infections. However, the latest Cochrane systematic review on the subject did not find convincing evidence these products actually are effective in UTI prevention in human patients. There is little research in veterinary patients, and unfortunately a new study in the American journal of Veterinary Research (AJVR) doesn’t add much information to help in deciding whether or not such products are useful.

Hsin-I Chou, Kuan-Sheng Chen, Hsien-Chi Wang, Wei-Ming Lee. Effects of cranberry extract on prevention of urinary tract infection in dogs and on adhesion of Escherichia coli to Madin-Darby canine kidney cells. American Journal of Veterinary Research Apr 2016, Vol. 77, No. 4, Pages 421-427.

This study consisted of two parts. The first involved treating dogs with a history of frequent urinary tract infections with either an antibiotic or a cranberry supplement and monitoring them for development of UTIs. The other involved mixing E. coli and canine kidney cells with urine from dogs given the cranberry supplement to see if there was any antibacterial effect or any impact on the adhesion of the bacteria to the kidney cells.

In the first part of the study, 12 dogs were split into two groups (it’s not clear if this was done randomly or not). These were dogs who had previously had recurrent UTIs, at least three times in the previous year. Six of the dogs were given a 2-week course of an antibiotic, and the other six were given a daily cranberry supplement for 6 months. All dogs had urine samples taken to look for infection once a month. None of the dogs developed a UTI during the 6-month monitoring period.

In the in vitro portion of the study, the urine from dogs given the cranberry supplement did not appear to have any inhibitory effects on bacterial growth. It did, however, seem to reduce the adhesion of these bacteria to canine kidney cells.

The design of this study is a little strange. There was no report of blinding or placebo control, and it is unclear if the subjects were randomly assigned to the two groups, so the risk of bias is difficult to assess. The strange thing, though, is that the comparison was between the cranberry supplement and a short course of an antibiotic rather than a placebo supplement. One would not expect a 2-week course of antibiotic to protect dogs from a urinary tract infection for 6 months. If resolving recurring UTIs were this easy, they would never happen since everyone would do this.

So in having no UTIs, the cranberry supplement group was no different from a group that received a treatment one wouldn’t expect to work, but which wasn’t a true placebo. It is very difficult to interpret this kind of comparison, but it certainly isn’t appropriate to say, it proves the supplement prevents infections, as the authors do. It is also not evidence that the supplement was safer than the short course of antibiotics, which the authors also claim. The lack of UTIs in all dogs may have been due to unexpected and dramatic effects from the antibiotics and the cranberry supplement which occurred despite these sorts of effects not having been seen in past studies. However, this may also reflect some other change in how these dogs were managed or simply the natural course of their disease. The purpose of controlled research is to help separate these possible causes, but this particular comparison doesn’t effectively accomplish that.

The second part of the experiment was consistent with past research showing that cranberry products do not inhibit bacterial growth but may reduce adhesion to urinary tract cells to some extent. Since kidney cells were used, it isn’t clear whether this effect would apply to cells in the bladder, where most urinary tract infections occur, or in actual living patients.

Bottom Line
The in vitro portion of this study is consistent with existing research that suggests cranberry extracts may reduce the ability of some bacteria to stick to the lining of the urinary tract. This could theoretically help prevent some urinary tract infections, though clinical research in human patients suggests this doesn’t really work to a significant extent in living people.

The portion of the study looking at prevention of UTIs in actual dogs, unfortunately, doesn’t help establish what benefit, if any, this product might have. No infections occurred in any of the dogs regardless of the treatment they got, and the comparison was between 6months of daily use of the cranberry product and a 2-week course of an antibiotic, which seems unlikely to effectively prevent UTIs for 6 months. This raises questions about whether either of the treatments were really responsible for the lack of UTIs in the dogs or if this was the result of the Hawthorne effect or some other source of error.

Posted in Science-Based Veterinary Medicine | 4 Comments

Possible Risk Factors for Kidney Disease in Cats

Chronic kidney disease (CKD) is a common and important cause of illness in older cats. It is a frustrating disease for many reasons, especially the lack of a clear understanding of what causes CKD and the absence of a proven effective strategy for preventing it. Many theories have been advanced for what causes CKD, but the existing evidence is not conclusive for any of them.

Particularly popular among alternative medicine advocates is the notion that commercial diets and vaccines are important causes. The role of diet is not at all well-established. There are some studies suggesting that certain vaccines can induce the formation of antibodies against proteins in the kidneys of cats, but this has not yet been linked to actual disease. A new study evaluating risk factors for CKD in cats adds both some useful data and also some confusion to the subject.

Finch, N.C., Syme, H.M. and Elliott, J. (2016), Risk Factors for Development of Chronic Kidney Disease in Cats. Journal of Veterinary Internal Medicine, 30: 602–610.

This study involved signing up a large number of cats in the U.K. and collecting data about many aspects of their life and health. These cats were then followed over time, and differences between those who developed CKD and those who didn’t were evaluated. The results can’t be taken as proof that these differences are or are not direct causes of CKD, but it can help to identify potential risk factors.

Many different factors were evaluated, though of course the number of potentially relevant variables is enormous, so many were not evaluated which might still be important. As is common in this sort of study, most factors tested did not appear to differ statistically between the groups while a few did. The type of statistical significance testing used has come under growing criticism, with the major organization representing statisticians recently producing an unprecedented position statement suggesting this strategy be abandoned as misleading. This complicates interpretation of this and most other scientific studies employing this method. The results are presented in the two tables below.

Finch 2016 Table 1 finch 2016 table 3

The first shows statistically significant differences in 3 of 12 variables compared, with more cats developing kidney diseases being predominantly outdoors, vaccinated every 1-2 years (as opposed to >/= 3 years or never), and having moderate to severe dental diseases. The second table shows the results of linear regression analysis intended to confirm statistical association between some of these variables and kidney disease. This analysis found statistically significant differences in 4 of 16 variables, with the risk of kidney disease being greater with increased age, vaccination more often than every 3 years, and moderate or severe dental disease. In this analysis, being predominantly outdoors did not reach statistical significance as a risk factor.

The association between vaccination and kidney disease in this study will undoubtedly fuel opposition to vaccination of cats among some owners and veterinarians. It is an important observation since it does suggest that vaccination may be a risk factor for this common disease. However, even if this is true, it suggests that the current vaccination guidelines, which include vaccinating no more than every three years and considering even fewer vaccinations in cats who are indoors only and not exposed to vaccine-preventable disease, are probably sufficient to eliminate or dramatically reduce this risk.

Unfortunately, no additional information about which vaccines might play a role and which components in those vaccines might increase the risk of kidney disease is available in this study. Until the potential association between vaccination and kidney disease is confirmed and a specific understanding of the causal relationships involved in available, the only reasonable response to the possible risk is to adhere to current vaccination guidelines. More radical action, as is likely to be advocated by anti-vaccine advocates, is not justifiable and will likely only increase the risk of preventable infectious disease without protecting cats from kidney disease.

The other variables associated with kidney disease in this study were dental disease, age, and possibly outdoor lifestyle. Because dental disease is a chronic infectious and inflammatory condition, it is quite plausible that this disease might increase the risk of kidney problems and other health conditions. This emphasizes the importance of good oral hygiene for cats. Age has long been associated with kidney disease, and confirming this does not provide much in the way of actions we can take to reduce kidney disease risk. Finally, the finding that predominantly outdoor living may increase kidney disease risk is interesting, but it would certainly need to be confirmed before we could confidently include this risk among the many known to be associated with letting cat roam freely outside.

The failure to find associations between some variables and kidney disease is also worth considering. No association was seen, for example, between diet and kidney disease. It is often claimed that commercial diets, particularly dry kibble, increases kidney disease risk. However, in this study at least, such an association was not supported.

As always, there are a number of limitations to this study that require us to interpret the findings with caution. The use of p-values, and the risk of evaluating many factors and drawing conclusions about the few that show a significant association has already been mentioned.

The other most significant concern is that almost half (43%) of the cats initially enrolled in the study dropped out, and no information about their development of kidney disease is available. If these cats differ in any way from the cats who were followed up, this could completely change the results of the study. Additionally, of the cats who were followed to the end of the study, only 27 developed kidney disease, which is a pretty tiny sample for this kind of epidemiologic survey. By comparison, several similar studies in humans have included between 4000 and 9000 individuals.

There are a number of other ways in which the cats in this study might not fairly represent other populations at risk for kidney disease. Most were from urban areas in the U.K., and there may be significant genetic and environmental differences between these cats and other populations, such as suburban or rural cats in the U.S. Also, much of the information about diet and vaccination was obtained from owners and was limited in detail and reliability. All of these factors influence the extent to which these results can be generalized.

Overall, this study highlights a few variables that might or might not influence the risk of kidney disease. Further study will be necessary to confirm both the positive and negative findings and elucidate the details of any real risk factors to allow meaningful action to be taken to reduce the risk of this common and serious disease.


Posted in Science-Based Veterinary Medicine | 2 Comments