The SkeptVet Blog

My recent brush with the “healthcare choice” concept, as well as a podcast interview I listened to with Dr. Paul Offit on Point of Inquiry put me in mind of an interesting and challenging puzzle in the philosophy of medical practice; the question of the tension between the role of health care providers as experts and the autonomy of patients of veterinary clients. I subsequently ran across an articulate and cogent discussion of this problem from the Annals of Internal Medicine, Physician Recommendations and Patient Autonomy: Finding a Balance between Physician Power and Patient Choice, which I highly recommend to anyone interested in understanding the complexities of the relationship between healthcare providers and patients.

Briefly, human medicine has traditionally followed the paternalistic model, in which the doctor is viewed as an expert with knowledge and skills the patient does not have. The doctor is expected to determine what is best for the patient and make the treatment decisions, which the patient is expected to accept. The disadvantages of this approach are obvious. As the authors of the article from the Annals put it, “it can be difficult to determine what a patient’s best interests are; inappropriate biases caused by sex, race and socioeconomic status can affect decision making; and patients can be deprived of the opportunity to make decisions that reflect the reality of their conditions.” The paternalistic model ultimate fails to give appropriate respect to the rights of patients to control their bodies and lives.

Many decisions made in the context of health care are not truly medical decisions so much as decisions about values. Quality of life, physical and emotional suffering, tolerance for risk, and many other factors affect the appropriateness of a given treatment plan that are subjective and truly accessible only to the patient. It is widely understood now that the paternalistic model is not ideal, and for at least 30 years most physicians have been trained in a more patient-centered model in which patient autonomy is properly valued.

What is less well-recognized, however, is that there are strengths and benefits associated with the paternalistic mindset. The reality is that despite the easy availability of large quantities of raw information, a deep and accurate understanding of medicine and the basic scientific principles underlying it is not readily available without the years of study and training health care providers undergo. The Internet has convinced us that we can quickly be experts in any area regardless of our personal abilities, skills, and experiences, but this is an illusion. Knowledge without understanding is dangerous because it leads us to confidently make poor decisions. The reality is that in the complex world of modern medicine even professional physicians can easily be overwhelmed by the required and ever-growing knowledge they need to make sound decisions, and lay people will only do poorer in judging the potential risks and benefits of particular interventions, no matter how much time they spend Googling the issue.

The alternative patient-centered or independent choice model of medicine has the obvious strength of giving proper respect to the autonomy of the patient and their feelings and values. However, in its extreme form it explicitly prohibits the doctor from offering recommendations or counsel, and limits the role of the provider to a neutral recitation of the statistical and technical features of various options among which the patient must choose entirely independently. This abdicates any responsibility for the welfare of the patient so long as autonomy is preserved.

There are some differences between human and veterinary medicine in how this tension between reliance on doctor expertise and authority and the autonomy of veterinary clients plays out. The paternalistic model was never fully realized in veterinary medicine due, in part, to the role of the animal patient in the lives of the clients. Traditionally dominated by agricultural applications, veterinary medical decision-making was long constrained by the need to focus on the utilitarian or economic value of the patient. Even non-agricultural animals were often viewed in a more utilitarian way than is now the rule, and the dominant model of companion animal medicine was not unlike that of auto mechanics. People would bring their dysfunctional pets to be repaired or, if this was not possible or the economic cost was too high, to be destroyed.

The profession has changed greatly, and now companion animal medicine is far larger a domain than agricultural practice, at least in terms of the number of veterinarians if not the total economic value of the industry. The prevailing model is much closer to that of pediatric human medicine than auto repair. Pets are commonly seen as individual family members, and the focus is on their health and well-being rather than their utility in most cases. Of course, economic limitations are still far more stringent than in human medicine, and the resources available are less, but very similar principles apply. The decisions made affect the patient directly, but the patient cannot themselves make decisions or even express their wishes. The interests of clients and patients sometimes conflict, and the veterinarian must attempt to serve both while maintaining acceptable professional and ethical standards and an economically viable practice.

The issues discussed in the Annals paper often arise in companion animal medicine. Many decisions, especially involving quality and end of life as well as economics, are value decisions rather than medical decisions, and so the autonomy and independence of the client must be respected. However, the doctor does have knowledge and understanding not available to most clients, and so ought to be able to offer guidance as well as factual information to assist in decision-making. What is more, the veterinarian has a duty to the patient, and protecting the patient’s interests sometimes requires working against the desires of the client.

How, then, do we negotiate the complexities of the veterinarian-patient-client relationship in a way that safeguards the interests of the patient, respects the values and autonomy of the client, makes optimal use of the expertise of the veterinarian, and is economically tenable for all parties? I cannot claim to have a comprehensive answer, but as always I have a  few thoughts.

To begin with, veterinarians should be trained to explicitly acknowledge the questions and issues involved. Very little time in vet school is spent discussing these concerns or how they might be addressed, and most veterinarians end up stumbling into an approach that seems to work for them with little or no guidance. As a consequence, practice styles range from those veterinarians who only discuss options they wish the client to pursue and who freely tell clients what they ought and ought not to do, to veterinarians who try to practice a strictly “independent choice” model and never make an explicit recommendation or voice any personal opinions in the consultation room. As is so often the case, the best solution seems to be between the extremes, and it is likely to be an ever-evolving, self-aware process rather than a rigidly fixed formula or algorithm.

The Annals paper discusses at length what the authors call the “enhanced autonomy” approach. Essentially, this involves trying to integrate the factual details of the medical situation with the values, feelings, and interests of the doctor and the patient through open and careful communication. While the patient must ultimately make the final decision about their own care, the doctor is not obligated to ignore the medical facts as they understand them, nor their own judgment. The authors describe the advantages of their model in this way:

“The independent choice model reflects a limited conceptualization of autonomy. Under this model, it is thought that an independent choice is best made with no external influence, even when one’s competence to make the choice is limited. However, autonomous medical choices are usually enhanced rather than undermined by the input and support of a well-informed physician. Only after a dialogue in which physician and patient aim to influence each other might the patient fully appreciate the medical possibilities…Enhancing patient autonomy requires that the physician engage in open dialogue, inform patients about therapeutic possibilities and their odds for success, explore both the patient’s values and their own, and then offer recommendations that consider both sets of values and experiences. This model is “relationship-centered”….rather than exclusively patient-centered. It denies neither the potential imbalance of power in the relationship nor the fact that some patients might be inappropriately manipulated or coerced by an overzealous physician. It assumes that an open dialogue, in which the physician frankly admits his or her biases, is ultimately a better protector of the patient’s right to autonomous choice than artificial neutrality would be. Because the biases of a physician will probably subtly infiltrate the conversation even if he or she tries hard to remain neutral, it may be better to explicitly label these values than to leave them outside of the conscious control of either participant.”

Such a model is well-suited to companion animal medicine as well. It requires first and foremost open acknowledgement of the roles both client and veterinarian play in making decisions for the patient. The veterinarian has knowledge and competence the client does not. They are able to appreciate the complexities of the medical situation, and they have the emotional objectivity to view potential outcomes realistically. The veterinarian also has a responsibility to advocate for the interests of the patient and to adhere to their own ethical and professional standards. Finally, the veterinarian has a fiduciary responsibility to the client.

The client has the ultimate responsibility for caring for their pet in a way consistent with their own values and resources. They understand the pet and their interests in a direct and personal way not available to the veterinarian. Therefore, the client must be the ultimate decision-maker regarding their pet’s care. However, part of their responsibility to the pet is to be aware of and attempt to compensate for the interference of their own interests with those of the pet. And as part of the duty to give the best care possible, the client should understand and acknowledge the need for the guidance the veterinarian can offer out of their deeper understanding of the medical questions at issue.

Interestingly, this model for the veterinary-client-patient relationship shares some features with the principles of evidence-based veterinary medicine. One widely used definition of EBVM, which I have cited before, is “the integration of the best research evidence available with clinical expertise as well as the unique needs or wishes of each client in clinical practice.” Balancing the best available information, which of course is primarily the province of the veterinarian, with the needs and wishes of the client requires both the client and the veterinarian to accept the limitations of their own knowledge. The client should defer in matters of medical fact to the veterinarian, who is in a better position to understand the medical issues in a deep and meaningful way. The veterinarian, in turn, should acknowledge the limitations of their own knowledge and experience and rely on the best and highest level evidence available to guide their recommendations. The doctor must also defer to the client in areas where the core issues are those of values rather than medicine, while of course still staying true to their own ethics and understanding of appropriate standards of care.

These negotiations between the interests and competencies of the parties involved are complex and situational, and they require explicit, clear communication, thoughtful self-reflection, and a willingness to consider and integrate factual information with sometimes contrary interests, values, and perspectives. This all makes the activity both difficult and sometimes frustrating and also richly rewarding.

CAM proponents are very fond of citing the antiquity and lineage, fictional or not, for their methods. Acupuncture, Traditional Chinese Medicine, and many herbal nostrums are promoted as “time-honored,” with the implication or explicit statement that anything people have been doing for so long must be a good thing. Foolishly expecting reason and logic to have some impact on this, we skeptics often try to point out that the number of people who believe something and the duration of time they believe it is not, unfortunately, a reliable indicator of whether or not it is BS. Or, as Tim Minchin more eloquently puts it in one of his songs, “I don’t believe that just because ideas are tenacious it means that they’re worthy.”

Soldiering on despite the blank stares or scoffing such a response often engenders, we continue to offer facts as rebuttal. The dramatic increase in life expectancy and health as scientific medicine came to replace traditional folk medicine seems a particularly salient fact in this context, but I recently ran across another smaller but more specific example of medical progress through time.

Dr. Atul Gawande, of Complications fame wrote an article for the New England Journal of Medicine in 2004 entitled Casualties of War–Military care for the wounded from Iraq and Afghanistan. As part of his discussion of care for wounded soldiers, he presented some historical statistics on the lethality of wounds suffered in combat by U.S. soldiers since the Revolutionary War. The table below illustrates the findings:

While we don’t have numbers from earlier eras or other countries, and while some caution is indicated in looking at numbers as old as those in the 18th and 19th centuries, the pattern is quite interesting. Survival varied, likely due in part to the reliability of the statistics, especially for small conflicts such as the Spanish-American War, but was consistently at or below 30% for most of the period until the 1950s. It improved to a consistent 25% for conflicts from then until the Iraq and Afghanistan conflicts and then improved dramatically. 90% of wounded soldiers can be expected to survive and come home, and while this raises legitimate questions about  how we ensure they have an acceptable quality of life and adequate help dealing with the lasting effects of their injuries, very few of them over the long term will likely prefer to have died. In this limited sense, such a change represents true progress in medical care for these servicepeople.

Dr. Gawande doesn’t address the changes prior to the current wars, but it seems likely that the development of antibiotics, blood replacement products, and other crucial developments in trauma care are responsible for the improvement after WW II. Gawande does delve into the details of the changes in medical practices that have dramatically improved survival in the current conflicts.

The point from the perspective of the difference between traditional and science-based medicine is that 1) the improvement coincides with major developments in scientific medical care which are often dismissed as irrelevant or even sources of harm and 2) medical practices are constantly being re-evaluated and improved based on measurable results. This is in stark contrast to the claims of those who argue for faith in tradition and received ancient wisdom.

Traditional folk medical practices have indeed often been around for centuries or even millennia, though these claims are sometimes exaggerated or fabricated by CAM advocates. However, in all those centuries or millennia, these methods have never succeeded in making the improvements in survival and health that have come in the last two hundred years, as Enlightenment rationality and scientific medicine have been born and matured. And these traditional practices are founded on the perceived virtue of not changing, whereas the ability to change and adapt that science gives mainstream medicine is one of its greatest strengths. This paper provides a small but clear illustration of the general case that the virtues of the scientific method demonstrably provide better results than the claimed virtues of tradition and longevity often attached to alternative medical practices.

One of the most popular nutritional supplements these days is fish oil. It contains a high proportion of omega 3 fatty acids (EFA), notable eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). This supplement is purported to have a broad range of beneficial effects in many disease conditions due to its effect on chemicals in the body involved in the inflammatory response (for more details see this article on eicosanoids). Some of these effects, such as a reduction in the rate of heart attacks in people with established heart disease and heart attack risk factors, are well-supported by research data. Other claims are less clearly valid. Several literature summaries are available from the Agency for Healthcare Research and Quality, and Medline.

In the veterinary arena, EFA supplements are widely used for allergic skin disease, with modest supportive clinical trial evidence (see also 1, 2, 3, 4).  In humans, there is limited evidence to support an effect on some clinical variables in patients with rheumatoid arthritis, and some have suggested osteoarthritis treatment as a veterinary application for these supplements. There is reasonable biologic plausibility to support investigating this use of EFA supplements, and two articles in a recent issue of the Journal of the American Veterinary Medical Association (JAVMA) report studies evaluating the use of fish oil supplements for dogs with confirmed osteoarthritis. I shall briefly review each of them.

The first study [1] was a multicenter, randomized, double-blind, placebo-controlled prospective study lasting 24 weeks. 167 dogs were randomized into two groups, one receiving a diet supplemented with EPA and DHA, the other receiving a pretty closely-matched control diet. There were no significant differences in any relevant variables between the groups at baseline. 23% of the dogs failed to complete the study (9% in the treatment group and 14% in the control group), and there were no significant differences between the groups with respect to these dropouts.

Assessment measures were subjective, with an owner survey and a clinical assessment by participating veterinarians. Dogs were evaluated at 6, 12, and 24 weeks after beginning the diets. Bloodwork showed significant increases in the blood levels of EHA and DHA in the dogs fed the test diet, so these substances were clearly absorbed. The owner survey evaluated 13 measures of comfort and function over three time periods (0-6 weeks, 6-12 weeks, and 12-24 weeks on the diets). Of these, 2 measures were significantly different between the groups at the first evaluation, and 1 measure was different at the last evaluation. There were no significant differences between the groups in clinical evaluation by veterinarians.

The study was apparently well-designed and well-conducted. The measures of outcome were subjective, which is less than ideal. It seems fairly clear that the results do not support the use of EFA supplementation for osteoarthritis. After all, out of 39 possible points at which the groups were compared in terms of owner evaluation only 3 showed changes not attributable to chance, and none of the evaluations by veterinarians showed significant difference. Unfortunately, the discussion section of the article is less an objective survey of the trial or the overall preponderance of the evidence than it is an attempt to put the most positive possible spin on the results.

The authors suggest their subjective measurement instrument may not have been sufficiently sensitive to detect a change and try to attribute the failure of the veterinarians to detect a difference to the hospital environment and limitations on clinical evaluation. They then conclude, “Our results suggest an ameliorative effect of omega-3 fatty acid supplementation in arthritic dogs,” and “ingestion of the test food….appeared to improve the arthritic condition in pet dogs with osteoarthritis.” Such a conclusion so clearly  at odds with the data presented in the report seems to be more an example of confirmation bias and cognitive dissonance than a reliable presentation of the evidence.

The second study [2] was conducted by several of the same authors. It too was a well-designed randomized, double-blinded, placebo-controlled, prospective study of the effects of dietary EFA supplementation on dogs with osteoarthritis. 44 dogs were enrolled in the study, and 14% failed to complete it (9% in the treatment group and 5% in the control group). Again there were no significant differences detected at baseline and no differences with respect to dogs that failed to finish the study. Both subjective and objective measures were evaluated at baseline and after 45 and then 90 days of the diets. Owner and clinician subjective evaluations were compared as were the results of force plate gait analysis.

In contrast to the previous study, there were no significant differences in owner evaluations of the subjects’ comfort and function. The authors attributed this to the low number of subjects rather than the more parsimonious explanation that there was no differences of sufficient magnitude to be noted. The clinician evaluations at 90 days showed significant differences from baseline for the test group in 3 of 5 measures. However, there were no significant differences between the test and control group for any measure.

The authors stated, correctly in my opinion, that “subjective assessment of limb function lacks repeatability as an outcome measure and is inferior to objective data obtained from force platform gait analysis.” Such an analysis was performed on all subjects. The results showed no change from baseline to 90 days for any of six variables measured (peak vertical force, vertical impulse, braking and propulsive peak forces, and braking and propulsive impulses). The test group did show a statistically significant difference in the mean percentage change in one measure, peak vertical force.

Again, these results provide lackluster support for the contention that EFA supplementation may be beneficial for dogs with osteoarthritis. Some subjective clinical measures showed a difference, but this is not consistent with the results of the other, larger trial, and the authors themselves minimized the significance of these results in both papers. One objective measure did show a statistically significant, and likely clinically significant change. However, the combined results of the two trials offer tepid support for the hypothesis under examination, and an interpretation of no meaningful effect seems much better supported by the results.

Unfortunately, the authors again spin these results in the most positive way possible:

“Together with the findings of our other study, findings of the study reported here supported the hypothesis that ingestion of fish oil omega-3 fatty acids improves clinical signs in dogs with osteoarthritis….Dietary supplementation with fish oil omega-3 fatty acids resulted in an improvement in weight bearing in dogs with osteoarthritis.”

The authors do acknowledge some of the limitations of their study and suggest that further research is necessary for definitive recommendations. I would agree that these results might justify further study, though I see no reason to expect dramatic findings of benefit. However, the reality is that in the world of veterinary medicine, with limited resources and clinical trial evidence, the more likely outcome of these reports is going to be an increase in the prescription for EFA supplements intended to treat osteoarthritis. The positive statements in the abstracts and discussion sections are likely to be the “take-home” message many readers get from the reports, despite the reality that the data is considerably less positive. I always appreciate well-designed and conducted research, but these reports emphasize the difficulty in conducting such trials without having an investment in their outcome that affects the interpretation of the results. This is a large part of why careful and critical evaluation of the primary literature for oneself is such a key component to sound, evidence-based practice.

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.

Mark Crislip at Science-Based Medicine recently discussed Hill’s Criteria of Causation, but after looking at Dr. Hill’s original paper I felt obliged to examine the subject here as well because it is central to science-based medicine, and key in differentiating real medicine from quackery.

As I often discuss, a crucial issue in medicine is the question of epistemology; how we know what we know. Our therapies ought to be based on a real understanding of health and illness, and sound evaluation of the safety and efficacy of the interventions we undertake. The key difference between scientific and alternative medicine is in the criteria  for such evaluation. CAM proponents are often satisfied with theories of disease than are either made up out of whole cloth by individuals (e.g. homeopathy, chiropractic) or that are an agglomeration of folk beliefs (e.g. acupuncture, reiki and other energy therapies, TCM). Whether these theories are consistent with our general understanding of the universe, or with each other, is not a concern.

Even more damning, CAM practitioners are frequently satisfied that their personal impressions and experiences are adequate to validate the truth of the causal associations they see underlying disease or in the response to their treatments. Despite the manifold errors the human mind is known to exhibit in making causal associations, these people don’t see any need for a type of validation that compensates for these errors. They may lay claim to any scientific evidence that can be found for their approaches, for the aura of legitimacy it confers, but they will never reject the conclusions of their experience or intuition in light of any other kind of evidence.

In 1965, Dr. Sir Austin Bradford Hill gave a talk to the Royal society of medicine entitled The Environment and Disease: Association or Causation? In this address, he laid out nine criteria for concluding that an observed association was in fact representative of a causal relationship. His lucid and cogent presentation provides us with an excellent framework for making decisions about the causes of disease or the effects of treatments, all the more because he was so careful to emphasize that his criteria were guidelines which should support, not replace critical thought and judgment.

Here are Dr. Hill’s criteria, with a brief explication of each:

1. Strength- The strength of an association can be supportive of a true underlying causal relationship. If a proposed cause for a disease is associated with the disease itself only sporadically or unpredictably, this is weaker evidence for its causal role than if it is reliably present in conjunction with the disease. As always, Dr. Hill cautioned that “we must not be too ready to dismiss a cause and effect hypothesis merely on the grounds that the observed association appears to be slight,” but the strength of an association is a relevant factor in evaluating its significance.

2. Consistency- An association between cause and effect should be robust enough to be demonstrable in multiple studies by different investigators. This is key to understanding the fallacy of presenting a single study as definitive evidence for or against a disease etiology or treatment effect. The preponderance of the evidence as it accumulates is more meaningful than the results of particular studies, though the quality as well as quantity of the evidence must also be considered.

3. Specificity- If a putative cause is associated with a very specific set of symptoms, or a treatment with very specific effects, this supports a causal relationship. If the cause is present with a wide variety of different clinical presentations or the results following a treatment are highly variable, this argues against a causal relationship. As always, Dr. Hill correctly cautions against excessive rigidity in the application of this criterion, pointing out that many diseases are multifactorial and may not exhibit great specificity of association with a single causal factor. As he puts it, “if specificity exists we may be able to draw conclusions without hesitation; if it is not apparent, we are not thereby necessarily left sitting irresolutely on the fence.”

4. Temporality- Causes by definition precede their effects, so if a potential causal agent is observed after the condition it is speculated to be causing, this argues strongly against a true etiologic relationship. The obverse of this is, of course, the post hoc ergo propter hoc fallacy, perhaps the most intransigent and troublesome reasoning error in medicine. The observation that one thing precedes another is not in any way evidence for a causal connection because of the myriad of alternative explanations that often turn out to dictate the order of precedence. Unfortunately, precedence is very compelling as proof of causality despite being unreliable.

5. Biological Gradient- Also known as a dose-response curve, this relationship is common in biological systems and is strongly supportive of a causal/effect relationship. If the amount of a drug given or the intensity of an exposure to a potential cause of disease is correlated with the likelihood or severity of the resultant effect or the disease, this supports a conclusion of causation. If, however, a little bit is as good (or bad) as a lot, the hypothesis of causation should be questioned.

6. Plausibility- Dr. Hill was less convinced of the reliability of this criterion because, as he correctly observed, “What is biologically plausible depends upon the biological knowledge of the day.” However, as he explains in discussing his subsequent criterion, a proposed relationship which contradicts well-established understandings in biology or other areas of knowledge should be viewed as less likely to be correct, and less worthy of implementation or investigation, than a relationship consistent with such understandings.

7. Coherence- In contrast to his caution regarding the criterion of plausibility, Dr. Hill states, “On the other hand, the cause-and-effect interpretation of our data should not seriously conflict with the generally known facts of the natural history and biology of the disease.” A proposed mechanism, such as that underlying homeopathy, which requires overturning well-established principles in biology, chemistry, and physics must face a far greater burden of proof to be accepted as valid than a hypothesis consistent with established knowledge.

8. Experiment- Clearly, the results of controlled laboratory, animal model, or clinical trial studies are critical in drawing firm conclusions about the causation of disease or the effects of medical interventions. Contrary to the stereotype sometimes promulgated by CAM advocates, scientific medicine does not rely solely on this criterion, but it can be a very powerful tool for confirming or invalidating proposed relationships.

9. Analogy- This is perhaps the weakest of Hill’s criteria, though it is popular because of the simplicity and apparent clarity of arguments by analogy. While toxins may cause illness, for example, not all illness should be attributed to toxins. Likewise, while infection may cause a fever, not all fevers are due to infection. Analogies are most useful for suggesting possible relationships, which should then be confirmed or disproven by application of more rigorous criteria.

After discussing his criteria, Dr. Hill goes on to eloquently addresses two critical issues in the epistemology of medicine. First, he is very clear that conclusions about cause and effect relationships must be based on assessment of multiple criteria and application of sound reasoning, not on slavish adherence to one criterion or to any algorithmic model, including his:

“What I do not believe – and this has been suggested – that we can usefully lay down some hard-and-fast rules of evidence that must be obeyed before we can accept cause and effect. None of my nine viewpoints can bring indisputable evidence for or against the cause-and-effect hypothesis and none can be required as a sine qua non. What they can do, with greater or less strength, is to help us to make up our minds on the fundamental question – is there any other way of explaining the set of facts before us, is there any other answer equally, or more, likely than cause and effect?”

This shows a sophistication of reasoning inconsistent with the stereotype of science-based medicine advocates as obsessed with randomized clinical trials and blind to all other evidence for or against proposed causal relationships.

Dr. Hill also presciently addresses the proper role of statistical analysis in medical decision making. In dealing with questions of cause and effect, he argues that “no formal test of significance can answer those questions. Such tests can, and should, remind us of the effects that the play of chance can create, and they will instruct us in the likely magnitude of those effects. Beyond that they contribute nothing to the “proof” of our hypothesis.” He goes on to discuss how statistical analysis entered medical research in the 1920s and 1930s as a needed anodyne to the practice of basing firm conclusions and therapeutic practices on small, not representative case examples. However, he speaks strongly of the excessive role such methods were then coming to play in drawing conclusions from medical research, and the problems he describes have only worsened in the intervening time:

“I am told, some editors of journals will return an article because tests of significance have not been applied. Yet there are innumerable situations in which they are totally unnecessary – because the difference is grotesquely obvious, because it is negligible, or because, whether it be formally significant or not, it is too small to be of any practical importance. What is worse the glitter of the t table diverts attention from the inadequacies of the fare….Of course I exaggerate. Yet too often I suspect we waste a deal of time, we grasp the shadow and lose the substance, we weaken our capacity to interpret the data and to take reasonable decisions whatever the value of P. And far too often we deduce ‘no difference’ from ‘no significant difference.’ Like fire, the chi-squared test is an excellent servant and a bad master.”

Lastly, Dr. Hill answers definitively and in no uncertain terms those critics who falsely accuse practitioners of science-based medicine of passivity or helplessness in the absence of definitive clinical trial evidence:

“Finally, in passing from association to causation I believe in ‘real life’….In asking for very strong evidence I would, however, repeat emphatically that this does not imply crossing every ‘t’, and swords with every critic, before we act.

All scientific work is incomplete – whether it be observational or experimental. All scientific work is liable to be upset or modified by advancing knowledge. That does not confer upon us a freedom to ignore the knowledge we already have, or to postpone the action that it appears to demand at a given time.

Who knows, asked Robert Browning, but the world may end tonight? True, but on available evidence most of us make ready to commute on 8:30 the next day.”

It is widely known by veterinarians, pet owners, and dog breeders that large breed puppies are at greater risk than other breeds for developmental disorders of the bones and joints, including hip dysplasia, elbow dysplasia, osteochondrosis dissecans (OCD), and hypertrophic osteodystrophy (HOD).[1,2] The breed predisposition for such disorders indicates a strong genetic component, however environmental factors can also influence the frequency of these disorders.[2,3] Nutrition during the growing period (birth until 10-12 months) is one of the most important factors influencing the development of these skeletal disorders. [2] Unfortunately, there are many myths about large breed puppy nutrition, so this article is an attempt to separate these from the real facts about developmental nutrition in large breed puppies.

Calories

By far the most important influence on the skeletal development of large breed puppies is total calories. Excess calories leads to more rapid growth and excess body weight, and these are associated with increased incidence of hip dysplasia, OCD, and elbow dysplasia.[4-8] Lower calorie diets do not reduce the ultimate stature a dog will achieve, but they reduce the rate of growth so that this size is achieved smoothly over the growth period rather than in a rapid burst.[9] This slower, more steady growth leads to fewer developmental orthopedic problems. he appropriate number of calories needed for optimal growth is different for every individual and depends on many factors. The best guideline for how much to feed is body condition. Several scoring systems are available (e.g. from Purina below), and puppies should be fed to an ideal condition (4/9 or 3/5).

Calcium

As with most nutrients, there is an optimal range of calcium levels for growing dogs. Both too much and not enough calcium can lead to developmental bone problems. For large breed dogs, this optimal range is narrower than for other breeds, and excessive levels of calcium cause OCD and other bone disorders earlier and with more severe consequences. While not all studies agree, the majority show a strong link between high calcium levels in the diet and bone problems, even when the levels of calories and other nutrients are the same. Though the level of calcium which increases the risk of skeletal problems varies with age, a calcium level of 210-540mg calcium per kilogram of body weight per day appears safe for large breed puppies of all ages. It is also important not to add vitamin and mineral supplements containing calcium to properly balanced puppy diets as this is very likely to increase calcium intake beyond safe levels. [2,5,10-12]

Protein

Many breeders and pet owners, as well as some veterinarians believe too much protein can contribute to developmental skeletal disorders in large breed puppies, but this is incorrect. An early study [5] observed orthopedic problems in dogs fed diets high in calories, protein, and calcium, but subsequent studies clarified that protein is not a risk factor for any of these problems.[13]

Diet Recommendations

The best way to meet the optimal dietary requirements for large breed puppies is with a commercial diet specifically designed for this purpose. Though many people recommend feeding an adult food, with the idea that it is lower in calories than regular puppy food, adult diets vary widely in calorie content, so this is not automatically true. Additionally, adult diets are not usually appropriately restricted in calcium content. It is also important not to add vitamin and mineral supplements containing calcium to properly balanced puppy diets as this is very likely to increase calcium intake beyond safe levels.

If you choose to feed a homemade diet or to supplement a commercial diet with table food or other additional ingredients, it is important to consult a nutritionist to ensure that the resulting diet has appropriate levels of calories and calcium to reduce the risk f developmental orthopedic disease.

References

1. Lauten SD. Nutritional risks to large-breed dogs: from weaning to the geriatric years. Vet Clin North Am Small Anim Pract. 2006 Nov;36(6):1345-59.

2. Hazewinkel H, Mott J. Main nutritional imbalances in osteoarticular diseases. In: Pibot P, Biourge V, Elliott D, editors. Encyclopedia of canine clinical nutrition. Aniwa SAS; 2006. p. 348-83.

3. LaFond E, Breur GJ, Austin CC. Breed susceptibility for developmental orthopedic diseases in dogs. J Am Anim Hosp Assoc. 2002 Sep-Oct;38(5):467-77.

4. Kealy RD, Lawler DF, Ballam JM, et al. Five-year longitudinal study on limited food consumption and development of osteoarthritis in coxofemoral joints of dogs. JAVMA. 1997;210:222-25.

5. Hedhamer A, Wu F, Krook L, et al. Overnutrition and skeletal disease: an experimental study in growing Great Dane dogs. Cornell Vet. 1974;64(1; Suppl 5):59.

6. Kastrom H. Nutrition, weight gain, and development of hip dysplasia. Acta Radiol. 1975;344(suppl):135.

7. Lavelle RB. The effect of overfeeding of a balanced complete commercial diet to a young group of Great Danes. In: Burger IH, Rivers JPW, editors. Nutrition of the dog and cat. Cambridge (MA), USA. Cambridge University Press; 1989. p. 303-15.

8. Grondalen J, Hedhammer A. Nutrition of the rapidly growing dog with special reference to skeletal disease. In: Anderson RS, editor. Nutrition and behavior in dogs and cats. Oxford, UK. 1982. 81-8.

9. Dammrich K. Relationship between nutrition and bone growth in large and giant dogs. J Nutr. 1991 Nov;121(11 Suppl):S114-21.

10. Hazelwinkel HAW, Goedegeburre SA, Poulos PW, et a;. Influence of chronic calcium excess on the skeletal development of growing Great Danes. J Amer Anim Hosp Assoc. 1985;21:337-91.

11. Schoenmakers I, Hazelwinkel HAW, Voorhout G, et al. Effects of diets with different calcium and phosphorus contents on the skeletal development and blood chemistry of growing Great Danes. Vet Rec. 2000;147:652-60.

12. Weber M, Martin L, Dumon H, et al. Growth and skeletal development in two large breeds fed 2 calciu levels. J Vet Int Med. 2000;388.

13. Nap RC, Hazelwinkel HAW, Voorhout G, et al. Growth and skeletal development in Great Dane pups fed different levels of protein intake. J Nutr. 1991;121:S107-113.

Too Thin

1  Ribs, lumbar vertebrae, pelvic bones and all bony prominences evident from a distance. No discernible body fat. Obvious loss of muscle mass.

2  Ribs, lumbar vertebrae and pelvic bones easily visible. No palpable fat. Some evidence of other bony prominence. Minimal loss of muscle mass.

3  Ribs easily palpated and may be visible with no palpable fat. Tops of lumbar vertebrae visible. Pelvic bones becoming prominent. Obvious waist.

Ideal

4  Ribs easily palpable, with minimal fat covering. Waist easily noted, viewed from above. Abdominal tuck evident.

5  Ribs palpable without excess fat covering. Waist observed behind ribs when viewed from above. Abdomen tucked up when viewed.

Too Heavy

6  Ribs palpable with slight excess fat covering. Waist is discernible viewed from above but is not prominent. Abdominal tuck apparent. 

7  Ribs palpable with difficulty; heavy fat cover. Noticeable fat deposits over lumbar area and base of tail. Waist absent or barely visible. Abdominal tuck may be present.

8  Ribs not palpable under very heavy fat cover, or palpable only with significant pressure. Heavy fat deposits over lumbar area and base of tail. Waist absent. No abdominal tuck. Obvious abdominal distension may be present.

9  Massive fat deposits over thorax, spine and base of tail. Waist and abdominal tuck absent. Fat deposits on neck and limbs. Obvious abdominal distention.

There are many dogmatic opinions available from veterinarians, pet owners, breeders and others concerning a common question owners of new puppies have, How much exercise is ok for puppies? This is an especially pertinent question for owners of large breed puppies, since these breeds have a higher incidence than others of developmental orthopedic disorders such as hip dysplasia, elbow dysplasia, and cartilage abnormalities known as osteochondrosis dissecans (OCD). As is all too often the case, however, these opinions generally lack solid scientific evidence to support them. Very little is known about the precise risks and benefits of different types and intensities of exercise in growing animals.

One case control observational study [1] surveyed dog owners and found playing with other dogs to be a risk factor for OCD. Another, similar study [2] found chasing balls and sticks was a risk factor for development of hip dysplasia and elbow abnormalities. However, these studies cannot answer the overall question, which is how much and what kinds of exercise pose how great a risk and provide how great a benefit. One study [3] found exercise to be part of the treatment of carpal laxity, another joint abnormality seen in large breed puppies, and there is no question that exercise has many benefits, including reducing the risk of obesity and simply being part of a normal, enjoyable life for a puppy.

There are many more studies on the effects of exercise in children than in puppies, and though it is always risky to extrapolate from one species to another, some useful information can be gained by using one organism as a model for another, as long as conclusions drawn in this way are cautious and tentative pending better data. In general, while some intense and repetitive exercise can pose a risk of damage to growth plates in children, exercise is overall seen as beneficial in improving bone density and reducing the risk of obesity and related health problems.

The research evidence, then, really does not provide anything like a definitive answer to questions about the effects of exercise in growing puppies. Common sense suggests that forcing a dog to exercise heavily when it does not wish to is not a good idea. Likewise, puppies sometimes have more enthusiasm than sense and can exercise to the point of heat exhaustion, blistered footpads, and other damage that may be less obvious. Therefore, a general principle of avoiding forced or voluntary extreme exercise is reasonable, but specific and absolute statements about what kind of exercise is allowed, what surfaces puppies should or should not exercise on, and so forth is merely opinion not supported by objective data. Such opinions may very well be informed by personal experience, and they may be reliable, but any opinion not founded on objective data must always be taken with a grain of salt and accepted provisionally until such data is available.

1. Slater MR, Scarlett JM, Donoghue S, Kaderly RE, Bonnett BN, Cockshutt J, et al. Diet and exercise as potential risk factors for osteochondritis dissecans in dogs. Am J Vet Res. 1992 Nov;53(11):2119-24.

2. Sallander MH, Hedhammar A, Trogen ME. Diet, exercise, and weight as risk factors in hip dysplasia and elbow arthrosis in Labrador Retrievers. J Nutr. 2006 Jul;136(7 Suppl):2050S-2052S.

3. Cetinkaya MA, Yardimci C, Sa?lam M. Carpal laxity syndrome in forty-three puppies.Vet Comp Orthop Traumatol. 2007;20(2):126-30.

Many pet owners have questions about neutering their pet dogs and cats, and while there is much useful information available on the Internet, there is also much misinformation. I have composed a literature review looking at the benefits and risks of spaying and neutering. It is too large to post directly here, so I have uploaded it as a .pdf file on SkeptVet.com. I hope also to soon have a simplified, tabular version for those disinclined to wade through the detailed consideration of all the pros and cons.

http://www.skeptvet.com/web_documents/NeuterProsCons.pdf

When I was training to be a veterinarian, an older vet once described the nature of his work this way, “I make decisions for a living.” After more than 8 years in practice, I know exactly what he meant. The process of taking the information I get from a pet owner and from my physical examination and then using it to set up a diagnostic and treatment plan involves making many, many decisions. Which pieces of information are important and which irrelevant? How reliable are the owner’s observations? What information from the pet’s previous history might shed light on the current problem? What additional information do I need to make a diagnosis? What diagnostic tests are likely to be safe, useful, affordable, and logistically feasible? What is the true diagnosis and what treatment should I recommend? How do I assess the response to treatment, both beneficial and adverse effects? What do I do if the owner declines some or all of my recommendations? What ultimately is in the best interests of the pet and will best promote their health and well-being? And on, and on, and on for multiple patients all day every day.

This is often an intellectually exciting and stimulating process. It is also often frustrating, especially when information I need is unavailable, or when I make the wrong decision, as I inevitably will sometimes being human. One of the greatest challenges, in both a positive and negative sense, is dealing with uncertainty. Lay people often view clinical medicine as a rather mathematical process. The see the doctor as taking historical and physical exam information, and maybe some diagnostic test results, plugging them into an algorithm established by experience, tradition, and scientific research, and coming out with The Answer printed in black and white at the bottom of the paper like an old-fashioned adding machine. When the doctor expresses uncertainty or inserts caveats into his description of the diagnosis or treatment, the client is likely to assume this represents a gap in the clinicians knowledge or competence. The Answer is presumably out there waiting for the right doctor to ask the right question or run the right tests and find it.

While there are particles of truth in this image, it ignores many sources of uncertainty. I’ve already mentioned one which bedevils the veterinarian, which is the often surprising lack of knowledge owners may have about their own pets. Historical information is notoriously unreliable, as are the theories, often supported with internet citations, that owners bring as to the nature of their companion’s problem. Now I realize the owner is most often the single best source of information about the pet, but even the most astute owner may not notice things that only a trained health care provider would notice, and many owners unfortunately can’t even tell me whether their animal is eating or eliminating normally.

Obviously, the information that can be obtained directly from the patient is often limited. Animals can show signs of pain, pruritis, and other physical sensations that might indicate what the problem is, but they cannot give the sort of precise descriptions of their symptoms we might hope for. And despite the claims of innumerable self-professed dog/cat/horse whisperers out there, there are serious dangers to accepting as reliable one’s own intuitive impressions of what an animal is feeling, as I discussed in my post on Animal Hospice care.

Other sources of uncertainty include the fundamental limits of our understanding. Though the progress of the last century in understanding the complex relationships that constitute physiology and the various causes and risk factors associated with disease is absolutely astounding, and continuing at a breakneck pace, the reality is there is much we still do not know. And the volume of what is known is so vast that it is impossible for any one individual to have an adequate command of all the relevant and constantly changing information needed to properly diagnose and treat any condition. Atul Gawande illustrates this limitation in human medicine beautifully in his book Complications, and it is even more of a factor for veterinarians who rarely specialize to the extent MDs do and who treat multiple species.

And while I take a risk venturing into the territory of epistemology, I think it is likely that much of the true, underlying nature of complex phenomena, like organisms and their health or diseases, is probabilistic rather than strictly deterministic. Certainly, in medicine we can often say with great accuracy how a group of patients with a particular condition will do over time based on research, but we are rarely able to say with any certainty how an individual patient with the condition will fare. While this may be due, to a large extent, to the lack of adequate knowledge and measurement capacity, it may also be due to a fundamental unpredictability to complex systems. Chaos theory, quantum mechanics, and the philosophical approaches grouped under the label of  indeterminism all address this possibility, and while it is true that these theories may not always be applicable to the problems of  everyday life (especially in the case of quantum mechanics, which applies, as far as we can determine, only at the subatomic level), they do suggest that not all natural phenomena are going to be amenable to precise, accurate prediction regardless of how accurate and detailed our information about them is.

Given, then that we must make important decisions with significant consequences on the basis of imperfect information and with the understanding that we will never be as accurate in our assessments and predictions as we would wish, what is the best strategy for making the necessary decisions anyway? First, there is a psychological hurdle we must overcome. I have seen some new veterinarians absolutely paralyzed with indecision when they first encounter the imperfect world of clinical medicine outside of the university. And some eventually give up practicing because it is too difficult to accept the reality that they will make imperfect choices and mistakes despite their best efforts, and that some of these will result in harm to their patients. For most of us, though, we must find the confidence necessary to deal with this reality and to accept that we can only do the best we can and that however imperfect it is better than if we did not even try.

I have seen far more veterinarians, unfortunately, cope with the uncertainties of medical decision making through an excess of confidence in themselves and their choices. Given that we do not have the detailed accounting of outcomes that MDs often have in hospitals, there are rarely formal mechanisms in place for a vet to determine how well they are doing their job, either in an absolute sense or in comparison to their peers. Confirmation bias, cognitive dissonance, and many other normal human cognitive predispositions make it very difficult for us to accurately assess our own performance. Like most people, we will tend to see what we want to see, which is that we are competent, caring, and effectively helpful. And while this is true for most veterinarians, the reality is that we likely overestimate our own abilities and underrate our flaws just like everybody else.

Other vets will deal with uncertainty by slavishly following formulae. Memorizing simple guidelines along the lines of “If THIS, then THAT” and applying them to every case is comforting in that it essentially eliminates decision making all together. Of course, it also eliminates assiduous observation and critical thought, which are essential for the practice of good, sophisticated medicine. One of the common objections to evidence-based medicine is that it is simply a way to enforce this sort of robotic algorithmic approach on everyone. As I’ll discuss, this isn’t really true, but the objection is at least founded on an appropriate disdain for such an approach.

It will come as no shock to those who are familiar with this blog that my answer to dealing with the uncertainties of medical decision making is to apply the paradigm of science-based medicine (SBM — strictly speaking, this is different in subtle but important ways from evidence-based medicine [EBM], but for present purposes they are essentially the same). I view taking on the SBM approach as something a bit like embarking on a 12-step recovery program. Below, I outline and discuss some of the steps involved. (There is, of course, a certain whimsical tone in such a presentation, but the content is an honest representation of the approach I believe veterinary medicine needs).

1. We must begin by admitting we have a problem. This is probably the most important, and certainly the most difficult of the steps. We must acknowledge that our decisions are limited by inevitable uncertainties and that while we can never achieve perfection we can do better with help than we do with a traditional reliance on our own experience, intuition, knowledge, and skills. The greatest resistance I get from other veterinarians to SBM stems from the idea that they don’t need it because they can reliably assess themselves and their diagnostic and treatment approaches just fine. A lot of what this blog is about is pointing out how mistaken this excessive and misplaced confidence is. I acknowledge that it is a natural response to the distress caused by uncertainty, but it is not the right strategy to cope with this distress.

2. Having accepted our limitations, we must be willing to overcome them. This involves educating ourselves about the specific weakness and limitations that diminish the quality of our decision making, It also involves taking concrete steps to address them even though this means letting go of familiar patterns of behavior and strategies that we are comfortable with and trying out new and unfamiliar approaches. We must have an ongoing, never-ending willingness to identify and acknowledge weakness in our knowledge and our practices and the courage to make changes even in long and dearly-held beliefs and behaviors.

3. Accepting that we need to change, we must acknowledge that there is a higher source of knowledge and evaluation than experience or tradition. This is, of course, the scientific method. We will rarely have as high a quality of evidence as we might like given the financial and logistical barriers to clinical and basic veterinary medical research. But we must be committed to accepting the conclusions of the best available evidence as more reliable than those of lower-quality sources of evidence such as our personal experiences. If well-designed and conducted research contradicts my intuition or personal clinical experience, I must be willing to defer to the more reliable source of information.

I do understand how very difficult this is for people in general, and doctors in particular I suspect. But it has been shown time and time again that the beliefs and intuitions of human beings, even multiplied by many people over extended periods of time, are inferior to the conclusions of reliable scientific research. The progress in medicine and the increase in the length and quality of our lives since we began moving away from faith-based and tradition-based medicine and towards science-based medicine is dramatic and incontrovertible.

4. We must then proceed to educate ourselves, our colleagues, and our clients. We must set up systems for generating reliable scientific information and making it easy to access for general practitioners. The Evidence-Based Veterinary Medical Association (EBVMA) is a group dedicated to doing precisely this, and I encourage all veterinarians and pet owners to support their work. Setting up resources such as online journal access, evidence-based reviews along the lines of the Cochrane Reviews, and other such tools would make it easier for practitioners to employ a science-based strategy.

However, they will only turn to this model if we who understand its benefits can make the case to our colleagues that they should, for the sake of their patients and clients. By education and by example, we have to show other veterinarians how the inevitable uncertainties in medical decision making can be minimized by an SBM strategy.

And we must educate our clients so that they can be more effective participants in their pets’ healthcare. Clients who understand the nature of medical decision making will be better able to make sound, informed choices among the options offered to them by their veterinarians. Client values and resources are a key factor determining what we can do for our patients, so we must include them in the decision-making process for practical as well as ethical and philosophical reasons. And the frustration and miscommunication that all too often taints the veterinarian/client relationship will be lessened if our clients understand that medicine is neither a straightforward mathematical process with clear right and wrong answers nor a mystical and vague “art” that depends solely on the talent and wisdom of a particular clinician.

As I mentioned earlier, the objection often made to SBM and EBM approaches is that they seek to impose a cookie-cutter uniformity and robotic system of rigid decision trees on clinicians. This might be true in a deterministic world with the availability of perfect information, but in the real world there will always be uncertainties and gray areas that require a thinking and caring doctor. Contrary to the impression I sometimes give, I believe that clinical experience and intuition are forms off evidence. They are very low-level evidence, and far less reliable that higher-level forms, but they are often all we have to go on, and they can serve us well if carefully and judiciously applied, with great humility. And even when the evidence is strong and we can define the medical parameters of a situation well, medical decisions often depend on non-medical decisions about values and interests. We may be able to say very accurately what the likely treatment outcomes are for a particular disease given the alternative choices, but that doesn’t necessarily tell us what the right thing to do is for a given patient and their family.

And in order for the veterinarian and client to work effectively as a team for the best interests of the pet, the vet must be able to understand and communicate the nature of the medical situation, the options available, and the inherent uncertainties in the decision-making process to the pet owner. All of these are reasons why even in the best case where SBM guides our practice, there is a need for the experience and skills of the veterinarian.

Many of my biggest concerns about CAM and the philosophy that underlies much of it are related to how uncertainty is handled. Many of the inappropriate responses to uncertainty I see mainstream veterinarians take sometimes are proudly adopted as foundational principles in CAM. Often uncertainty is denied entirely, with CAM practitioners claiming all diseases can be definitively traced to a simple causal schema (unbalanced ch’i or humours, innate intelligence blocked by subluxations, toxins, and so on). Denying differences between individuals, species, or diseases and blaming all illness on universal vitalist forces gone awry is the ultimate abdication of responsibility for making careful, informed medical judgments.

Uncertainty in treatment outcomes are often denied as well. Worsening of the patient’s condition is frequently taken by homeopaths to be a sign of improvement, a so-called “healing crisis.” Of course, improvement in symptoms is also taken as a sign of improvement, so there’s no way to lose! As I’ve related before, CAM believers are often unwilling or unable to admit any room for improvement in the wisdom received from millennia or centuries or decades of tradition. While I believe the best response to uncertainty is open acknowledgement of it and an ongoing effort to improve and change, tradition-based practices are founded on the principle of preserving and not questioning received wisdom. And the reliance on anecdote and testimonial commonly seen in CAM venerates the individual experience and intuition. However, I believe less rather than more respect for this form of evidence is the key to more effectively managing the uncertainty in decision making.

Finally, in case I haven’t emphasized it sufficiently, I believe that a degree of uncertainty and unpredictability is intrinsic to medicine and we will never be free of it. Accepting this ourselves as veterinarians or our clients as owners to make perfect decisions is vital to providing good care. Recognizing our limitations not only helps us accept a better methodology, but it frees us from the illusion that we can be perfect or that we can control all outcomes for all of our patients. This makes us not only better doctors but, I suspect, happier people.

Over the last several decades, attitudes towards pets and their role in our households have change dramatically, and in my opinion for the better. Many pet owners see their animal companions as family members rather than objects of utility and entertainment. Pets are brought to the veterinarian with goals and expectations more like those of a parent bringing their child to the pediatrician than of an owner bringing a broken car to the mechanic.

This change in attitude has supported progress in the quality of veterinary care. Better attention to pain control and quality of life, more and better therapies, and of course the expectation that veterinarians will follow the principles of evidence-based medicine that are the standard of care in the human medical field are all positive developments in the profession made possible by clients’ growing desire to have the best care for their animal companions.

And as pet care has improved and our pets have come to live longer, we are more frequently confronted with the issues associated with caring for geriatric patients. Older pets will often have complex and multifaceted medical problems. They may suffer from chronic diseases, including degenerative processes such as osteoarthritis and loss of hearing, vision, mobility, continence, appetite, weight, and even cognitive and behavioral functions. And ultimately our pets will come to the end of their lives, and an important part of our work as veterinarians is helping our patients and their owners through this part of the life cycle.

Because pets are more and more members of the family, owners may not simply wish to euthanize at the first sign of serious disease. Veterinarians can and should be able to support their clients through the process of accepting and grieving for the impending loss of a pet while still strongly advocating for the interests of their patients. Unfortunately, training and resources to help veterinarians do this effectively are scarce, and vets may not be aware that there is more they can offer besides steroids and euthanasia.

In human medicine, the hospice model has become the dominant approach to end-of-life care. While there are many different specific forms hospice care can take, in general the philosophy is to palliate the clinical symptoms of the dying person and also support the patient and the family through the logistical, psychological, and often spiritual aspects of the dying process.

The emergence of hospice represents a salutary change in cultural attitudes which more and more accept that death is part of the life cycle and need not be denied or hidden away. Dying people and their families deserve physical and psychological comfort, and if medical and allied health care personnel are accepting and comfortable with the dying process they can better provide appropriate care.

Of course, in general euthanasia is not an option for people at the end of their lives, and it is a common practice in veterinary medicine, and widely accepted as appropriate medically and morally. So the hospice model has been slow to gain acceptance in the veterinary medical community. However, there are veterinarians and others working to bring this practice to our pets. I think many of the attitudes and practices of hospice are desperately needed in the veterinary field. Like the rest of our culture, I think veterinary medicine would benefit tremendously from a more accepting attitude towards death and dying, and I think our patients and clients can and should receive better care and comfort from us even when we can no longer substantively influence severe disease processes.

However, I am also concerned that some of the people involved in this movement may be bringing irrational ideas and approaches to the process which may ultimately end causing rather than relieving suffering for our patients.

The International Association for Animal Hospice and Palliative Care (IAAHPC)  has recently been established, with the stated mission to promote hospice care and establish protocols and standards for such care. The organization was founded after a symposium on animal hospice held March, 2008 at the University of California Davis. The existence of differing, and sometimes incompatible philosophies regarding hospice care are hinted at on the IAAHPC website:

“IAAHPC is committed to being an organization that is inclusive in its philosophy; it will represent different professions and differing viewpoints of animal hospice/palliative care, end of life, and death and dying.

Some in the animal hospice movement see their own views as diametrically opposed to other views. But whether we like it or not, the animals and society will be best served by focusing on our common interests and by respecting our differences.”

A little investigating of the organization’s board of directors provides some insight into these differences. A number of the members are strong advocates of CAVM practices and critical of mainstream veterinary medicine. Dr. Ella Bittel is a “holistic” veterinarian with strong CAM credentials. She practices acupuncture, chiropractic, homeopathy, Bach flower therapy, and TTOUCH and other energy therapies. She is also an active member of a number of CAVM lobbying groups and has published in the  Journal of the American Holistic Veterinary Medical Association on the topic of hospice care. In her article, she is suggests that “holistic” veterinarians are more likely to embrace the hospice process and paints a rather bleak picture of mainstream veterinarians forcing euthanasia on their clients and “disenfranchising clients from their basic right to chose[sic] what they feel is best for the animal they have cared for throughout its entire life.”

In her other writings, Dr. Bittel frequently promotes the value of CAVM therapies for relieving discomfort or preserving function when “Western” medicine has failed. As I have discussed before, most of these assertions are unproven or outright false. Dr. Bittel  also makes frequent reference to an animal’s “will to live” and “dying wishes,” which she suggests owners and caregivers can intuit through a “hunch,” “tuning in with a calm mind,” and so on. She describes poignantly her loss of her own dog, and includes as a vital facet in making care decisions her inner sense of what her pet wanted.  

I respect the energy that Dr. Bittel is putting into promoting the hospice concept, and I agree with her that there is a need for better end-of-life care for our pets. However, I reject the cliché that she puts forward  that veterinarians who describe themselves as “holistic” are in any real way truly more aware of or interested in the welfare of their patients as whole beings. “Holistic” has strayed far from its literal meaning to become merely a shibboleth indicating a faith commitment to unproven or outright bogus medical approaches, often relying heavily on vitalism and a vague New Age mélange of spiritual beliefs. Homeopathy, Bach flower therapy, and “energy medicine” offer no real relief of suffering for our patients, and they offer only the limited comfort of placebo by proxy for our clients. I have seen many patients suffering clear and obvious pain because their owners refused to see that the faith-based medicine they were using was failing, and because they had irrational fear of real medical therapies. Cognitive dissonance and other forms of denial are powerful, and we do our patients no service by helping our clients to deceive themselves that their pets are comfortable and happy when they are in fact suffering.

Pet owners desperately want to hold on to their beloved companions as long as possible. Owners and veterinarians want the pets we care for to be happy and well, and we want our efforts on their behalf to be successful. It is all too easy to project these desires onto our pets and see what we want to see. Promoting subjective, intuitive methods of divining what our pets “true” feelings and desires are, and discounting the behavioral signs available to us, as Dr. Bittel sometimes suggests, is a dangerous practice that promotes such emotional projection and the mistaking of our desires and interests for those of our animal companions.

Examples of tragic harm that can be caused by such approaches abounds in human medicine, including the fads of Facilitated Communication and Repressed Memory Therapy. I have had numerous encounters with pet psychics or “animal communicators” who claimed to speak for the inner thoughts and feelings of some of my patients. They often provide vague, reasonable statements that could apply to any animal at any time. They certainly appear to comfort clients, and I have never seen one claim to intuit something from an animal that a clients really didn’t want to hear. But I have also seen the worst of them flagrantly pander to the client’s inability to accept the inevitable loss of their pet and continue to re-assure them their companion was content and did not want to be euthanized despite obvious and awful suffering. Such irrational methods for making decisions about quality of  life, palliative care, and euthanasia are not in our pets’ best interests and have no place in veterinary hospice care.

Other members of the IAAHPC founding board besides Dr. Bittel also promote a “holistic” or CAVM-based approach to veterinary care, including Gail Pope, who is affiliate with a “Holistic Animal Retreat” which promotes homeopathy and “animal communication” as part of its services. The philosophical and epistemological perspectives of other board members isn’t readily apparent, and I suspect from the reference to “difference” quoted above that some are strongly in favor of a science-based approach to end-of–life care.

Certainly, there is no need for absolute uniformity in clinical practice related to hospice care, and the IAAHPC statement is correct that the goal of improving end-of-life veterinary care is important enough to warrant attempts to find common ground and accommodation among veterinarians with different approaches. However, if the flagship organization for the hospice movement, the group setting the standards for the profession, is ultimately dominated by faith-based medicine and  misleading vitalist philosophies, then the standards that are adopted may very well do more harm than good.

Euthanasia should certainly not be the only or first recourse in serious terminal illness, but neither should it be shunned as “unnatural” or discouraged on the basis of “intuitive” methods of quality-of-life assessment that project the owners needs and wishes onto the patients. And while homeopathy or flower essences may give the owner the comfort of imagining they are doing something to contribute to their pets’ wellbeing, they should by no means be used in lieu of truly effective therapies for control of pain, nausea, and other discomfort associated with dying. Every attempt should be made to ensure that the methods of assessing the condition of the pet and the response to palliative therapy, and the therapies that are employed, are consistent with the best evidence and most sound scientific principles possible. No one should deny our clients the comfort of  rituals and spiritual practices that they may wish to invoke when their pets are sick or dying. But just as parents cannot legally or morally deny their children the best scientific medical care available on the basis of religious or other faith-centered beliefs, so animals who are dying should not be denied adequate palliation and euthanasia on the basis of such beliefs. I believe there is much of value in the hospice approach that can and should be brought into veterinary medicine, but I also believe that to do hospice the right way and truly improve the care we give, we must stick to science and evidence-based medical practices.

A news report from The Olympian newspaper reports a localized outbreak of parvoviral enteritis, or “Parvo” in Southwest Idaho. According to the article, “Veterinary clinics and hospitals in Boise, Nampa and Caldwell are all reporting a spike in canines with symptoms of parvovirus. In some Treasure Valley clinics, the increase is 10 times the normal rate.”

Parvo is caused by a virus shed in the feces of infected dogs. Puppies are especially vulnerable to infection between 8 and 20 weeks of age, when the antibodies they receive from nursing gradually decline and their own immune system has not yet produced enough antibodies to be protective. Some breeds are more sensitive to the virus than others, but any puppy can become infected. And the virus is very robust, able to remain infective in the environment for months.

With a series of vaccinations, the disease can almost always be prevented. As discussed in my primer on veterinary vaccines, a series is necessary because the maternal antibodies block the vaccines, and the puppies own antibodies are produced gradually over time and take a while to reach protective levels. It is true that surviving the disease will lead to protective antibody levels, often for life. However, 20% of puppies with the disease will die, and many others will experience needless suffering.

Local vets in the area of the outbreak are theorizing that dog owners are neglecting to get all of the recommended puppy vaccine series due to the troubled economy. As the article correctly states, “The vaccine for parvovirus is very, very effective, 99.9 percent effective. It’s unfortunate to see so many cases because it does not have to happen,” said Dr. Kayla Williams of the Blayney Veterinary Clinic, which has treated 30 cases in the last four weeks.”

Outbreaks like this are unfortunate, but they provide needed reminders that vaccination is critical to prevent diseases like parvoviral enteritis, which persist at low levels in the population waiting for a lapse in vaccination to re-emerge as an epidemic. Vaccines are another medical tool that are in some ways hurt by their very success. Anti-vaccine propaganda can convince people such diseases are no longer a threat because most people who have properly vaccinated their pets will never see a case. Here is yet another piece of evidence that this is a dangerous myth.