Orientalism

Posted on October 12, 2010 by skeptvet

One of the more subtle flaws in thinking that supports unproven alternative medical approaches is the notion best described by Edward Said in his book Orientalism. Though I don’t agree with Said’s post-modernist approach in general, I see great utility in the concepts labeled by the term “orientalism.” Essentially, this term refers to a process of mythologizing and idealizing non-Western cultures and projecting our own agenda onto them, rather than trying to objectively see and understand the complex, messy reality of such cultures. Said’s focus was the Middle East, but the same process applies to indigenous cultures throughout the world.

Sometimes, orientalism takes the form of obvious prejudice, such as reference to “ignorant savages” and the like. But more often, especially among the post-modern left wing intelligentsia which so often also advocates for alternative medical approaches as “equivalent ways of knowing” alongside science, the form orientalism takes is more sophisticated. It often involves an expression of admiration for the purity or simplicity of cultures not tainted by modern scientific or political ideas or other products of the Renaissance and Enlightenment in Europe. Non-Western cultures, and people, are sanitized and seen as exotic and not polluted by the moral or intellectual conflicts that decadent imperialist Western cultures suffer from.

This, of course, is ignorant and patronizing and merely another form of racism which ignores the fundamental commonalities of human beings and human cultures as well as the complexities and conflicts that characterize non-Western societies as much as our own. But it is difficult to convince the dedicated orientalist of this since their sense of admiration for the exotic seems to them like respect rather than simple patronizing psychological projection.

Cracked.com has an entertaining, but oddly sobering piece up today on the subject which pretty much says it all:

5 Examples of Americans Thinking Foreign People are Magic

Posted in General, Humor | 8 Comments

Cognitive Dissonance In Action: Glucosamine No Matter What!

Posted on October 11, 2010 by skeptvet

I’ve discussed cognitive dissonance previously. Briefly, it is the unpleasant feeling that comes from a conflict between beliefs, and its most typical manifestation is a powerful ability to rationalize away evidence that contradicts what we believe. Rather than experience the discomfort of recognizing and accepting that our beliefs are mistaken, and that as a consequence we may have acted inappropriately, we simply find ways to dismiss even powerful evidence and cling to our false beliefs.

I recently came across a classic example on the blog of a “holistic” veterinarian. The evidence, which I’ve reviewed before (HERE, and HERE, for example) is quite clear that in humans oral glucosamine and chondroitin are no better than a placebo for arthritis. And the limited evidence available in veterinary medicine provides no better support for these supplements. As the evidence against these products accumulate, the rational thing to do is to re-evaluate our use of them and honestly advise our clients that the best we can say is they are harmless and may have minimal benefit for selected individuals. This, however, is problematic for those with strong ideological commitment to supplements being superior in terms of safety and efficacy to conventional medicines.

The vet in question acknowledges that recent research suggests a lack of effectiveness for these products, but his response has more to do with his biases than a rational analysis of the risks and benefits of various therapies.

If consumers believe some of the recently published articles that purport to show a lack of effectiveness for joint supplements, my concern is that they will turn to chronic NSAID usage which could be harmful or even fatal due to the well-known side effects (kidney disease, liver disease, worsening of the arthritis, gastrointestinal ulcers and perforations) of this class of medications.

So, if consumers realize glusosamine isn’t doing anything for their pets, they might be tempted to switch to drugs that actually do help? Isn’t that awful!

There is no question NSAIDs have potential side effects. Any medication that has benefits does. The issue is whether we are better off giving our pets an absolutely safe product that does nothing, or a very safe product that really helps. Research clearly shows NSAIDs have undeniable benefits for arthritis patients, far greater than any potential benefits of glucosamine products.[1,2] And the safety record is very good, with serious side effects in only a small percentage of cases, even with long-term use, and with most problems associated with inappropriate use (dose higher than recommended or used at the same time with steroids or other NSAIDs)[3-5] These drugs can worsen pre-existing kidney or liver disease, but this is preventable with appropriate screening and monitoring. The can cause gastrointestinal ulceration in a small percentage of patients, though this is rarely clinically significant. They do not worsen arthritis. And, as the good holistic vet neglects to mention, these medicines actually do treat arthritis effectively, unlike glucosamine.

The mental contortions involved in continuing to recommend an ineffective product can be quite complicated. In addition to ignoring the benefits of NSAIDs and the lack of benefits to glucosamine and focusing only on risks, the denial of reality involves ignoring research findings if one can find anecdotes or personal beliefs that contradict them.

Additionally, many consumers currently using joint supplements experience the positive effects commonly seen with these products, including relief from pain, reduced inflammation, reduce joint swelling, and increased mobility. While skeptics may claim it is only a placebo effect (and in some case they may be correct,) if the end result is an improved quality of life, does it really matter why the patient feels better or gets better?

This response not only inappropriately privileges anecdote over research evidences, it also reflects a common misunderstanding of the placebo effect. It is not a case of “mind over matter” in which the patient gets better because they believe they are being treated. It is a case of patients believing they are better and reporting a positive effect when their disease has not actually changed. One can argue this may be of some real benefit for people with subjective symptoms, like pain and nausea, since thinking you feel better might in some sense actually be feeling better. But the effects are always small (far less than those of  truly effective medicines), they don’t last, they don’t change the underlying disease process, and they require the healthcare provider to either be wrong about whether the treatment actually works or to lie about it. Is this really better than using medicines that have high benefits and some risks?

This vet then exaggerates his own personal experiences and ignores the many ways in which veterinarians and owners can be mistaken about the effects of a treatment, to present what looks like a incontrovertible case against the research findings.

In my own veterinary practice, the placebo effect cannot occur. Either my canine and feline patients improve and begin walking, or they don’t and they remain lame. I have seen thousands of pets improve when administered joint supplements and taken off of NSAID medications. Neither the owners or I were making this up. Either the pet walks or it doesn’t walk: this is not a placebo effect.

This makes it sound like this fellow has seen thousands of pets who couldn’t get up take glucosamine and then rise and walk. If these products really are such a miracle drug, why isn’t this obvious to everybody else taking or prescribing them? I suspect the truth is that he recommends glucosamine for dogs with signs of arthritis, and later the owners say “Gee, I think Fluffy’s walking better!” This may be true, but it’s also quite likely may be a result of the  “placebo by proxy effect.” This is a combination of many of the cognitive errors I’ve written about before: Regression to the mean/natural course of disease (in which a patient with a waxing and waning problem comes in right when the symptoms are at their worst and are just about to get better as part of the natural course of the condition); expectancy (in which the owner expects to see some improvement as a result of the time, effort, and money they’ve spent on seeing the vet and so convinces themselves they have); and all the inadequacies of subjective, external evaluation of an animal’s level of pain that make real, objective research in this area so vital.

Finally, this alternative vet comes right out and says that he doesn’t believe the research, because it contradicts his personal experiences, and that he has no intention of re-evaluating his beliefs regardless of what evidence comes to light.

While I appreciate ongoing research into the use of joint supplements, I still encourage people to use joint supplements for themselves and to administer them to their pets. I have seen the effectiveness of these products and have also seen the horrible side effects of chronic NSAID usage. While researchers can continue to fight over the effectiveness of joint supplements, I will continue to use them and other treatments that help improve the lives of my patients.

This is the paradigm of cognitive dissonance and faith-based medicine. The same reasoning supported millennia of bloodletting and all manner of useless, even harmful therapies that modern medicine has only been able to dislodge by demonstrating that we must have the humility to accept our personal observations are less reliable than true scientific evidence, and the courage to acknowledge when we have been mistaken and change our ways. No such humility or courage is possible with a deep ideological commitment to alternative ways and an irrational suspicion of all things based in mainstream science. For all that advocates of such an approach call for “open-mindedness” regarding their own ideas, they don’t very often evince it when it comes to the evidence against their favorite therapies.

References

1. Aragon, C.L., Hofmeister, E.H., Budsberg, S.C., Systematic review of clinical trials of treatments for osteoarthritis in dogs. J Am Vet Med Assoc 2007; Feb 15;230(4):514-21.

2. Moreau, M., et al. Clinical evaluation of a nutraceutical, carprofen, and meloxicam for the treatment of dogs with osteoarthritis. Vet Rec 2003; 152:323-329

3. Innes JF, Clayton J, Lascelles BD. Review of the safety and efficacy of long-term NSAID use in the treatment of canine osteoarthritis. Vet Rec. 2010 Feb 20;166(8):226-30.

4. Lascelles BDX, Blikslager AT, Fox SM, Reece D. Gastrointestinal tract perforation in dogs treated with a selective cyclooxygenase-2 inhibitor:29 cases (2002–2003). J Amer Vet Med Assoc 2005; 227(7):1112-7.

5. Neiger R. NSAID-induced gastrointestinal adverse effects in dogs—can we avoid them? J Vet Intern Med 2003;17:259–261.

Posted in General, Herbs and Supplements | 9 Comments

Home Remedies: A Cautionary Tale

Posted on October 7, 2010 by skeptvet

Harriett Hall, The SkepDoc from whom I cribbed my moniker, recently wrote on the science-Based Medicine blog about the new Mayo Clinic guide to home remedies, which sounds like a sensible guide to appropriate kinds of self-treatment for minor medical problems. Despite the accusations of the fringes of the alternative medicine movement, that doctors are driven by greed and love to provide unnecessary treatment for minor ailments, the reality is that doctors prefer to treat the truly ill, not those with problems that will resolve themselves. People who go to the doctor with self-limiting viral infections for which there is no effective treatment are accomplishing nothing other than sharing their virus with their healthcare providers, so if they could treat their own symptoms at home I’m sure their doctors would be thrilled. And I frequently discuss with my clients both indications that a pet needs to come in to see me and indications that they don’t and can be managed by their owners at home.

The thing is, most mild ailments do get better all by themselves. This is one of the reasons nonsense therapies often seem to work. If you have a common cold, a headache, an upset tummy from too much spicy chili, and so on, you are likely to feel better pretty soon no matter what you do. So home remedies are fine if they make you feel better (by placebo or real effects), or if they just give you something to do while waiting to get better.

The key, though, is that while it isn’t so important if home remedies are effective, since they are only appropriate for mild, self-limiting illnesses, it is critical that they be benign. Any remedy that does harm for a mild disease that’s going to get better on its own is automatically doing more harm than good, unlike a medication which may cause harm that is worth tolerating in order to treat a more serious disease.

I had a case the other day which exemplifies the problem with home remedies: ineffective and potentially harmful treatments applied with no understanding of medicine or even common sense. An otherwise healthy cat had developed some patches of hair loss which the owner self-diagnosed as ringworm (a fungal infection). The owner attempted to treat this with a commonly recommended remedy of vinegar and grapefruit seed extract. There is no good quality evidence this mixture is effective even if ringworm is present, though some laboratory research suggests grapefruit seed extract may have little effect on this particular kind of fungus, and like many “natural” remedies may have contaminates that can present a health hazard.

The cat developed vomiting, diarrhea, and a loss of appetite after licking itself where the remedy was applied. The owner attempted to treat this with activated charcoal and probiotics. I’ve written about probiotics in general (as well as about specific uses and studies and some of the more egregiously fraudulent marketing of them), and there is some plausibility to the idea they may be useful for some kinds of diarrhea, though this is not at all proven in dogs and cats. And activated charcoal is an appropriate agent to give animals suspected of ingesting poison, since it can reduce absorption of the toxins. However, a cardinal rule of treating toxin exposures is never give oral medications, especially charcoal, to an animal that is vomiting. Not only will these likely incite more vomiting, but there is a great risk of aspirating the charcoal into the lungs, which can cause a serious pneumonia. This was clearly a case where a home remedy was not indicated.

The client brought the pet in and was given some suggestions about medications and feeding, with the main suggestion being to let the cat alone. The hardest thing for any pet owner to do when their companion is sick is nothing, even when that’s the best thing to do. Like many people who feel they need little or no veterinary advice to treat their own pets, the owner had a stock of left over medications previously prescribed for other pets which the person was eager to use. And in the absence of being told to use them, the client was eager to apply home remedies rather than simply give the cat time to recover naturally.

The next day, the cat was no longer vomiting but didn’t want to eat and still had soft stools. In addition to giving the cat a variety of foods, including some clearly inappropriate for a patient with a gastrointestinal problem, such as egg yolks, the owner then attempted to treat the diarrhea by giving the cat two enemas, one with aloe vera and another with flax seed oil. Apart from the lack of any evidence to suggest either of these substances have benefit for GI upset, and the utter ridiculousness of the colon cleansing and intestinal toxicity ideas, the notion of treating diarrhea by giving enemas is every bit as stupid as it sounds. Such treatment is not only going to further aggravate the original problem but can potentially cause serious injury, especially performed by someone without proper training in an inadequately controlled environment.

The clearest evidence of this person’s complete lack of not only medical knowledge but even common sense was when they seemed both worried and puzzled by the fact that the cat was reluctant to be picked up or touched near the hind end by the owner!

Home remedies are perfectly appropriate for mild, self-limiting conditions, as long as the remedies themselves do no harm. But as this case illustrates, determining when it makes sense to use such remedies, and what kinds of treatments are appropriate for what conditions, is not apparently as straightforward as proponents of treating your own pets at home would have you believe. No doubt most pet owners are sensible enough, and have enough understanding of the limitations in their own knowledge and skill, to be trusted to recognize when their pets need professional care and when they can try using simple home remedies themselves. However, in my years of practicing I have seen many, many cases of unbelievably inappropriate treatments and horrible neglect due to a complete lack of any understanding by owners of what is mild and what is serious disease and what remedies they can reasonably apply on their own, so I believe we must be very cautious when telling pet owners they don’t necessarily need to seek veterinary care when their pets are sick.

The most important part of any guide to home remedies should not be the treatments themselves, those these should of course at least be safe. The most important thing such a guide should emphasize is that owners must recognize the limitations of their own medical knowledge and understanding and know when to call their vet. Ultimately, home remedies may or may not effectively treat symptoms, but they are only appropriate if they do no harm and if they are used for conditions that are going to get better on their own regardless of whether we do anything at all.

Posted in General, Miscellaneous CAVM | 6 Comments

Does the Pheromone DAP Reduce Stress in Dogs Having Surgery?

Posted on September 26, 2010 by skeptvet

In June I reported on a systematic review of the behavioral effects of pheromones on dogs and cats. That review examined all the studies to date on pheromone products such as Feliway and DAP (dog appeasing pheromone) and concluded that there was almost no real evidence that these products had meaningful behavioral effects. There is an abundance of literature, most of it produced or at least funded by the companies selling these products, that they have some measurable effects on any number of physical or behavioral measures. But that is entirely different from demonstrating that they actually make pets feel or behave better.

A new study has been published in the most recent Journal of the American Veterinary Association, examining whether or not DAP has an effect of indicators of stress or pain in healthy shelter dogs undergoing routine spaying and neutering:

Siracusa C, Manteca X, Cuenca R, del Mar Alcala M, Alba A, et al. Effect of a synthetic appeasing pheromone on behavioral, neuroendocrine, immune, and acute-phase perioperative stress response in dogs. Journal American Veterinary Medical Association 2010;237(6):p. 673-81.

This is a nicely designed study of 46 dogs in residence at an animal shelter in Spain for at least 20 days. There is no indication of how the dogs were chosen, though the exclusion criteria for the study are clear and appropriate, and the treatment (DAP or an appropriate placebo) was randomly assigned. Investigators were effectively blinded to the treatment assignments.

A large variety of behavioral and physiological variables were assessed. Subjects were videotaped in their usual environment, and then in the surgical area before and after surgery. These videotapes were scored after the fact for 31 behavioral variables. In addition, a previously described interactive test for evaluation of pain was performed after surgery.

Putative physiologic measures of stress (salivary cortisol levels, prolactin levels, white blood cell counts, blood glucose levels, and acute-phase protein levels) were measured before and after transfer of the subjects to the surgical area and after surgery. Having done research on behavioral enrichment and well-being in captive primates prior to veterinary school, I am aware that there are problems with the utility and reliability of these variables in assessing stress or well-being, but they are commonly used and reasonable markers as long as their weakness are kept in mind.

The results were a significant difference between groups for the change in two behavioral variables, visual exploration and alertness. DAP-treated subjects appeared to have less of a decrease in these behaviors after surgery than placebo-treated dogs. The significance of this isn’t really clear. The groups did not differ in any other behaviors, including those more seemingly relevant to discomfort or stress such as vocalizing, licking oneself, moving around, etc. There was also no difference between the groups in pain as assessed by the interactive assessment used in this study.

Of the physiologic variables, the ones traditionally associated with stress (again, with much debate among ethologists about their usefulness), such as cortisol levels and lymphocytes counts, did not differ between the groups. The only physiologic variable that did differ was the level of prolactin in the blood.

Prolactin is a hormone usually associated with nursing, as it is released in response to suckling and is involved in stimulating the release of milk. It does have some other behavioral affects associated with reproduction and maternal care behaviors, but its significance in terms of stress or pain is not clear. Some changes in blood levels have been associated with stressors such as surgery or with the presence of behavioral problems, such as anxiety disorders, but the role of prolactin in behavior and stress is not well characterized.

So in this small but well-designed and conducted study, we see a couple of variables apparently affected by the presence of the DAP, though none of those usually associated with the negative aspects of the surgical experience, such as pain or activation of the stress response system as reflected in cortisol levels. What can we conclude from this? Well, in these dogs under these circumstances, DAP diminishes the decrease in prolactin levels following surgery, and it might have some impact on general alertness and looking around.

Does this have any meaningful significance for the comfort or well being of the dogs in the study, or other patients in similar circumstances? Not that we can conclude from these results. The fact that an intervention appears to do something is a big leap from the kinds of claims made by the manufacturer of the commercial DAP product. These marketing materials describe this as “the secret to happy dogs” and suggest “It is strongly advised that puppies wear a DAP® Collar throughout the socialisation period (from 6-16 weeks) to prevent fear and stress which may lead to anxiety-related behavioural problems later in life [and] to dramatically influence a puppy’s development and help it grow into a well-behaved and confident adult dog.” A good bit beyond the kind of real data seen in this paper or the previous review of the published literature.

It is possible that purified or synthetic pheromones may ultimately have a role to play in treating behavioral problems in dogs and cats, or in otherwise ameliorating the stresses associated with illness and medical care. But the products currently on the market, and widely used, have so far not done a very impressive job of proving their value. Harmless? Probably. But also perfect candidate for placebo-by-proxy effects, making owners and veterinarians feel better rather than our patients.

Posted in Science-Based Veterinary Medicine | 6 Comments

Theory of Superstitious and Magical Beliefs

Posted on September 21, 2010 by skeptvet

Lindeman M, Aarnio K. Superstitious, magical, and paranormal beliefs: An integrative model. Journal of Research in Personality 2007;41:731-44.

I recently ran across this paper in the Journal of Research In Personality which had some interesting things to say about how people come to have beliefs in superstitions or paranormal phenomenon. This is relevant to the issue of alternative medicine both directly, since so many alternative approaches rely on vitalism or notions of magical forces (acupuncture, homeopathy, chiropractic, reiki, etc) and also since the mental mechanisms underlying false beliefs in general likely apply to many different categories of belief.

I have said many times that I do not think false beliefs in medicine, even in the wackiest and most ridiculous ideas, have any consistent relationship to how smart people are, and only a tenuous relationship to an individual’s level of education. There are mistakes we all make in thinking that lead us to erroneous conclusions, and there is a whole literature in the field of psychology which examines these. It is clear that such mistakes are built into how we think, into the very structure of our brains, and the reason science works better than the alternative epistemological approaches is because it does a pretty good job of taking our subjective judgments, and their weakness, out of the assessment of efficacy for medical therapies.

This article tries to create a “unified theory” of superstition, and then does some preliminary testing of subjects identified in previous research as unusually skeptical or superstitious. Such research is itself fraught with subjectivity, so I am always a bit suspicious of it, but I find the theorizing an interesting and potentially useful way of looking at the problem of magical beliefs.

The authors contend that research in child development has identified some core beliefs about the world that are intuitive and nearly universal. These beliefs concern physics, psychology, and to a limited extent biology. For example, young children intuitively understand kinematics, the laws which govern the motion of objects through space, and can correctly describe and predict the behavior of billiard balls and other such simple physical objects intuitively, without any conscious or rational knowledge or deliberate instruction in the relevant physics. Likewise, they intuitively understand the concepts of mind, intention, and agency, which allows them to predict the behavior of people and animals pretty well. Finally, they have some intuitive concepts, like the ideas of contagion and healing, related to biology.

These intuitive understandings are retained in adulthood, though they can be modified somewhat by rational knowledge. As grownups, we are able to understand (sometimes, anyway), the mathematics of objects in motion and able to use this knowledge to master more complex examples such as spaceships and missiles, through rational knowledge and thought. But we still pretty much catch and throw balls intuitively, using the same largely innate understanding that first appears in children. The same pattern applies to our understanding of psychology and biology, in which we retain our intuitive knowledge while modifying or supplementing, and maybe sometimes supplanting, it with rational, acquired knowledge.

The authors then suggest that the defining characteristic of superstitious beliefs is confusing the properties intuitively understood to operate in one area, such as psychology, with a different category, such as physics. So, for example, the intuitive understanding that people act in certain ways because of their intentions and beliefs is applied to inanimate objects, and so intention and purpose is ascribed to the behavior of things which do not truly have such features. Thus lightening can strike someone intentionally, as a punishment for bad behavior. Or dice can be made to roll a certain number by the power of thoughts or rituals.

Furthermore, superstitions require that this conflating of intuitive knowledge across distinct categories not be checked adequately by rational thought or knowledge. While we may fear to handle the clothing of someone who is ill, due to an intuitive understanding of the principle of contagion, if we truly belief we can “catch” cancer or a genetic disorder in this way, these beliefs become a superstition if not overridden by our rational knowledge and thought.

The pilot survey study the authors conducted looked at whether skeptical or superstitious people were more or less likely to confound properties across categories in this way, and whether one group was more or less inclined to rely on intuitive or rational knowledge. Not surprisingly, the results showed that skeptics are less likely to confuse properties from different domains and rely less on intuitive knowledge than superstitious people.

As I said, I am a bit suspicious of the objectivity and reliability of such assessments, and I am certainly not qualified to evaluate the authors’ assessment of previous research nor the methods they used in their own study. However, apart from the empirical portion of the paper, I found the theoretical discussion interesting, and I look forward to seeing if it proves useful in examining false beliefs in the area of medicine.

Posted in General | 4 Comments

Nope, Glucosamine and Chondroitin Still Don’t Work in Humans

Posted on September 19, 2010 by skeptvet

Just one more nail in the lid that’s never coming off the coffin of glucosamine and chondroitin. Despite the ubiquity of these supplements and the innumerable testimonials for their benefits in people and in pets, the research continues to accumulate that they are nothing more than a placebo when it comes to treating arthritis pain. A new meta-analysis in the British Medical Journal looking at 10 trials with over 3800 patients followed for up to 2 years found no clinically significant affect of glucosamine or chondroitin supplementation on pain scores of joint width (a measure on cartilage degradation). Not surprisingly, industry-funded trials tended to have more positive results than independently-funded trials.

Of course, people will argue that this is not directly relevant to the use of these supplements in dogs and cats, and we should not discount their potential value in these species without similar high-quality studies. There is some truth to this, but given the limitations in resources and technical difficulties of veterinary research, the absence of any plausible reason to think that these products might perform better in animals than in humans, and the uninspiring results of the non-industry funded veterinary research on glucosamine and chondroitin so far, it would seem to be placing our bets on the long shot to put much more of our limited resources into studying these therapies.

Then again, it’s hard to find a dog, cat, or horse that isn’t already on glucosamine and chondroitin, so a cynic might ask whether the evidence really matters or not anyway. Luckily, I am an inexhaustible well of optimism about human nature, so I would never be so cynical. 🙂

Posted in Herbs and Supplements | 3 Comments

Another Study of Fish Oil for Canine Arthritis

Posted on September 15, 2010 by skeptvet

In January, a couple of research studies were published in the Journal of the American Veterinary Medical Association (JAVMA) investigating the possible usefulness of dietary fish oil supplementation for treating the symptoms of arthritis in dogs.[1-2] I have previously discussed these papers in detail, but overall they were well-designed studies with mostly negative findings. However, the few statistically significant measures seen were generously interpreted as evidence for a beneficial effect of the treatment. A more accurate interpretation would be that no clear, consistent, meaningful effect was observed. Still, the few effects that were documented would justify additional research. Ideally, this research would be conducted by different researchers since the group naturally has a bias in favor of the intervention they are studying, and a number of the authors of the JAVMA studies have institutional affiliations with the Hill’s Pet Food company which manufactures the diet with supplemental fish oil tested in the study, and this raises some possibility of a conflict of interest. 

However, the same research group has now published another study looking at fish oils as a treatment for canine arthritis, this time in the Journal of Veterinary Internal Medicine.[3] This study was specifically designed to look for effects of varying levels of fish oil supplementation on subjective measures of arthritis.

A Bad Beginning
My first concern about this study is the background statement and introduction, which begin with the claim that “Food supplemented with fish oil improves clinical signs and weight bearing in dogs with osteoarthritis (OA).” The evidentiary support for this claim is twofold. First, it is supported by reference to findings in humans that fish oils may improve the symptoms of rheumatoid arthritis. There is some limited evidence that this may be the case (c.f. literature summaries available from the Agency for Healthcare Research and Quality, and Medline), however even if this were established, the relevance is questionable since this is a different disease in a different species. The authors acknowledge that “the pathophysiology of rheumatoid arthritis and OA differ,” but they let stand the implication that since both are inflammatory conditions, if fish oil helps one it might help the other. Plausible but very weak reasoning.

The second major pillar of support for the a priori claim that fish oils are proven effective as a treatment for canine arthritis is, you guessed it, the two previous papers published by the same group in JAVMA. Obviously, given my review of these papers, I don’t consider that claim to be justified by those studies. So this study begins with the assumption the treatment works, and the hypothesis is then examined that since some helps more might help even more.  Shaky ground to start from.

The Study
As with the previous work, the study was soundly designed. 212 dogs were randomly assigned to eat one of three diets with different levels of fish oils but relatively comparable otherwise. The diet with the lowest level of fish oil (Diet A) was the same as used in the previous studies, approximately 0.8% EPA+DHA on a dry matter basis. Diet B had ~ 2% of the fish oils, and Diet C about 2.9%. There was no negative control (diet without supplemental fish oils).

Subjects were allowed to use concurrent therapies, including NSAIDs and glucosamine, but no overall statistically significant difference in the rate of such usage was found between the groups of patients on the different diets. Dropout rates were moderate and higher for Food A than the other two foods (Food A-22%, Food B-13%, Food C-17%). The authors state that the inclusion evaluation data from dogs that did not complete the study did not affect the results. Owners and participating veterinarians were blinded to the treatment individual dogs were assigned to.

The assessment measures included a series of subjective physical examination parameters assessed by participating veterinarians similar to those used by the participating veterinarians in the previous studies. These were performed on Days 0, 21, 45, and 90 of the study. Two new variables were included, which were general questions the participating vets were asked at the conclusion of the study:

A. “Based on the pet owner’s input and your own clinical assessment, how would you describe the impact the study food has had on this dog’s arthritic condition?”
1. significantly slowed progression of the arthritis
2. slightly slowed progression of the arthritis
3. no effect
4. slightly accelerated progression of the arthritis
5. significantly progression of the arthritis

B. “Based on the pet owner’s input and your own clinical assessment, how has the arthritic condition of this dog changed since eating the study food?”
1. extreme improvement
2. moderate improvement
3. slight improvement
4. no change
5. slight deterioration
6. moderate deterioration
7. extreme deterioration

The authors also measured the blood levels of a variety of omega-3 and omega-6 fatty acids for all subjects.

The Results
Serum levels of omega 3 fatty acids increased significantly more for Foods B and C than for Food A, showing that greater levels in the food correlates with greater levels in the actual animal. Some omega 6 fatty acid levels were significantly lower in subjects eating Foods B and C, others were not.

In terms of the 5 clinical evaluations done by participating veterinarians, all improved significantly over time for all diets except that the score for weight bearing did not improve for Food A. Of the 5 measures, 2 improved more for Food C than for Food A, and there was no difference between Food B and Food A.

For the two subjective questions asked of the participating veterinarians, the answers showed a statistically greater improvement for Food C than for Food A, and again no difference between Foods A and B.

Sixteen adverse events were recorded, and of these 2 cases of vomiting and/or diarrhea were attributed to the intervention (one for Food A and one for Food B). What the other events were and why they were not considered related to the diets was not discussed. 

Discussion
So, do fish oils effectively treat the symptoms of canine osteoarthritis? Maybe. Improvements were seen for all foods. The measures were subjective, and the two summary questions asked of veterinarians in the study were structured in a redundant and somewhat leading way, so there are some limitations in the reliability of the conclusions based on these. Interestingly, the authors claim these results are consistent with their previous studies, but this is not entirely true. In one of the earlier studies, no veterinarian clinical examination measures improved, and only 3 out of 39 possible data points for owner evaluation improved significantly. In the other study, none of the owner evaluations changed significantly, but 3 of 5 measures evaluated by clinicians showed improvement. An objective measure, force plate gait analysis, was used in this second study, and this showed no change from baseline for any of 6 variables but a significant mean improvement for 1 of the 6 measures.

By contrast, in the current study only subjective veterinarian evaluations were used as measures of outcome, and these showed improvements in all variables for all foods. The authors point out that these improvements were “relatively modest” (aka small), but rather than attributing this to the treatment having only a modest effect, they attribute it to the insensitivity of their subjective measurement criteria. This is a bit odd since in medical research generally, subjective criteria are much more likely to show positive changes than objective criteria, even when there aren’t any real differences.

The inconsistency in the results of the various trials is a cause for concern, as it suggests the criteria for measuring any possible treatment effect may not be reliable. The trials designed to see if the treatment worked found few and inconsistent positive changes in subjective measures and almost no change in objective measures. The trial designed to see if more worked better than less found that everything worked a little, but while the difference between the diet with 0.8% fatty acid content and that with 2% was not significant for any measure, the difference between 0.8% and 2.9% was significant for 2 of 5 clinical measures and both global assessment questions asked of the participating vets. And all of this is ignoring the potential biases introduced by having all trials done by the same research group and the association with a company manufacturing a commercial food used in all of the trials.

This does not create a solid, consistent pattern of evidence to support the use of fish oils to treat canine arthritis. At best, it can be said that: the serum fatty acid level data indicates the fish oil changes the fatty acid profile of dogs in ways that would be desirable if the fish oil actually has clinically meaningful effects;  there is weak evidence to suggest there may be some such effects, though small and inconsistent; and there is little evidence of short-term harm.

All of this is useful data, of course, and generally the studies were well-conducted. However, the conclusions tend to be much stronger than is justified by the data, which is a reflection of the bias of the investigators in favor of the intervention they are researching. This is to be expected, but if a small group of researchers become the only source of clinical data on the subject, and if most vets read only the conclusions and don’t critically examine the studies and the results, it is likely to have an inappropriately large impact on clinical practices. I wouldn’t be surprised if fish oil for arthritis becomes the new glucosamine, and while I hope it turn out to work better than glucosamine does, that product had much the same kind of weak positive data from limited sources at the beginning as well, and now it has become a ubiquitous product despite subsequently stronger results suggesting it has no benefit.

References
1. Roush JK, Dodd CE, Fritsch DA, Allen TA, Jewell DE, et al. Multicenter veterinary practice assessment of the effects of omega-3 fatty acids on osteoarthritis in dogs. J Am Vet Med Assoc. 2010 Jan 1;236(1):59-66.

2. Roush JK, Cross AR, Renberg WC, Dodd CE, Sixby KA,, et al. Evaluation of the effects of dietary supplementation with fish oil omega-3 fatty acids on weight bearing in dogs with osteoarthritis. J Am Vet Med Assoc. 2010 Jan 1;236(1):63-73.

3. Fritsch D, Allen TA, Dodd CE, Jewell DE, Sixby PS, et al. Dose-titration effects of fish oil in osteoarthritis dogs. J Vet Int Med 2010;24(5):1020-26.

Posted in Herbs and Supplements | 5 Comments

Evaluating Risks and Benefits of Neutering Dogs and Cats

Posted on September 15, 2010 by skeptvet

In response to questions from clients, and a lot of myths embedded in them, I set about last year reviewing the literature concerning the risks and benefits of neutering dogs and cats. This led to a handout for owners, which is available here. When this came out, I got some encouragement to produce a formal literature review for vets on the subject, and this has just been released in the online journal CAB Reviews. For those of you interested and with access to the journal, the article can be found here:

Evaluating the benefits and risks of neutering dogs and cats
CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources 2010 5, No. 045

Abstract

Neutering consists of removing the source of the hormones that control reproduction and determine secondary sexual characteristics. In dogs and cats, this is most commonly accomplished by castration or ovariectomy. While the primary purpose of neutering is to prevent reproduction, the procedure may have other physical and behavioural effects.

Epidemiologic research has identified many beneficial and harmful outcomes associated with neutering. A definitively causal relationship between these outcomes and neuter status cannot be accepted without consistent evidence from multiple studies of adequate size and quality. However, consideration of the possible health consequences of these associations is warranted when offering owners recommendations concerning neutering.

An evidence-based decision about neutering a particular pet requires integrating relevant research data with the veterinarian’s clinical expertise and the needs and circumstances of the patient and owner. It is impossible to precisely predict the outcome of neutering for any individual. However, existing research does allow some generalization about the magnitude and clinical importance of specific risks and benefits. Overall, it appears justified to recommend spaying all females not intended for breeding, because the procedure is more likely to prevent rather than cause disease. In male dogs, the benefits of castration are not so clearly greater than the risks. The evidence is also mixed regarding the risks and benefits of neutering dogs before 5–6 months of age, and so no strong recommendation for or against the practice can be made. However, it is clear that spaying female dogs before their first heat is preferable to spaying them later.

Posted in Science-Based Veterinary Medicine | 21 Comments

Eureka! Latest Breakthrough in Homeopathy!

Posted on September 14, 2010 by skeptvet

At last, I’ve figured out how to get rich and cure every disease. Writing about homeopathy yesterday got me to thinking. There is a plethora of potential homeopathic remedies not available or used by either conventional medicine or advocates of alternative medicine simply out of blind prejudice: homeopathic pharmaceuticals! Conventional doctors would reject the idea because they have an unreasonable prejudice against the notion that water can cure everything. And homeopaths would probably reject using “drugs” even though they are diluted to the point where there is nothing left but water.

But think about the possibilities! The principle of homeopathy is that whatever causes a given symptom in a proving on a healthy subject will, when diluted and shaken properly, alleviate that symptom in an ill patient. What better source of compounds that cause every imaginable symptom could there be but conventional pharmaceuticals!

Take prednisone, a much maligned steroid. At therapeutic doses in the short term, it can cause an increase in appetite, urination, and drinking. Chronic use can cause thinning of skin, muscle wasting, and infections. So dilute it, shake it and Bingo: Treats the increased urination of chronic kidney failure! Suppresses appetite for weight loss! Builds muscle strength for agility competition! Can even treat infections!

Or how about morphine? Therapeutic doses are very effective for pain but can cause nausea. So homeopathic morphine would treat nausea, but unfortunately anything over about 30C would probably cause unbearable pain!

At last, the solution to all my patients’ problems, and my student loans.

Posted in Homeopathy, Humor | 2 Comments

Care and Use of Homeopathic Remedies

Posted on September 13, 2010 by skeptvet

It always feels a little cruel to poke fun at homeopathy since it is perilously close to self-parody already, particularly the serious and earnest way in which proponents say absurd things. As a refresher, the idea is based on a couple of ideas made up by Samuel Hahneman in the 19th century. You take something that makes you sick, or causes a particular symptom (maybe, though most “provings” are based on Hahneman or someone else swallowing something, usually diluted to the point at which there is nothing but water there, and then reporting how they feel). Anyway, then you dilute it some more (and don’t forget to shake it!) until it becomes a potent but completely safe remedy.

Even the homeopaths don’t claim there’s anything but water in most of their nostrums, but they believe the water has some “memory” of what used to be in it (but only what they put in it, not the animal poo or whatever else was in it before they got hold of it). This is often “explained” with reference to quantum physics, since almost no one really understands quantum physics well enough to recognize this as BS, and besides it sounds better than calling it “magic.”

But I recently ran across a bit of advice from the American Holistic Veterinary Medical Association that deserve a little mockery. Here is their handout on Care and Use of Homeopathic Remedies:

Care and use of homeopathic remedies 

  • Fill bottle with spring water if not already diluted
  • Store in refrigerator unless otherwise labeled 
  • Tap bottle 10-20X against palm of hand before administering .This mixes the remedies, but also increases their effectiveness  
  • Wipe off tip of dropper when done to minimize contamination. In dogs, you can squirt the remedy into the cheek pouch  
  • Do not mix in food or water if possible. (the water bowl is a possibility for single pet, difficult-to-medicate pets).Just let Dr. Lund know that you are using the remedy this way
  • Your bottle will last ~6-8 weeks, and then often start to grow a bit of mold. Pets on long term therapy will need a recheck by then anyway, and the next set of remedies is usually different

So let’s get this straight. First, you dilute the water with spring water, unless it’s already been diluted. Then store the water in the refrigerator, presumably to prevent it from spoiling. Shake the water before administering to mix it with itself and make it an even stronger medicine. Be very careful not to mix the water with any food or water, except the water you originally mixed the water with (presumably too much water would make the water dangerously strong). And don’t worry if the water grows mold despite being refrigerated, since by the time this happens it will probably be necessary to have another visit with the doctor and change to a different kind of water anyway.

Obviously, I’m not smart enough to practice this kind of medicine.

Posted in Homeopathy, Humor | 8 Comments