One of the most popular subjects for discussion and debate in pet health for many years now has been the relative merits of commercial pet foods and unconventional diets of various types, including homemade cooked and raw diets, commercial raw diets, vegetarian diets, etc. Some pet owners and veterinarians have concerns about the safety and health effects of commercial diets, though only some of these concerns have any real evidence to support them, and most of the negative claims about commercial pet food are unsupported or simply inaccurate.
Most veterinarians are more concerned about the safety and nutritional adequacy of unconventional diets. Homemade cooked diets have been repeatedly shown to be unbalanced and nutritionally incomplete if not formulated by veterinary nutrition specialists. Diets incorporating raw meat, both commercial and homemade, present a serious risk of food-borne infectious disease to pets and humans (1, 2, 3, 4, 5, 6). Vegetarian diets may be adequate for dogs if carefully formulated, but they are likely unsafe for cats, and there are no demonstrated benefits for either species.
Subjectively, there seems to have been an increase in pet owners’ interest in and use of unconventional diets n the two decades I have been in practice. While most do still feed at least some commercial cooked foods, many are experimenting with homemade or raw diets despite the risks and lack of evidence for any benefits. A new study has tried to assess how popular such diets really are and how this has changed over time.
Dodd, S., Cave, N., Abood, S., Shoveller, A., Adolphe, J., Verbrugghe, A.
(2020) An observational study of pet feeding practices and how these have changed between 2008 and 2018 Veterinary Record Published Online First: 18 June 2020. doi:10.1136/vr.105828
The authors began by reviewing the literature for previous studies that investigated pet owners’ feeding practices. They then conducted an online survey asking pet owners about their use of conventional, homemade, and raw diets. The results suggest that while most people still use conventional and cooked diets, the inclusion of raw and unconventional diets is increasing. There also appear to be some regional differences in feeding practices. The table below summarizes the comparison of the current study with past reports.
Overall, the results suggest that most pet owners feed some conventional commercial food to their pets. However, it also appears that a higher percentage of owners include homemade cooked or raw foods as some or all of the diet for their animals. Well over half of the respondents indicated they feed at least some raw animal products, and in some locations (e.g. Australia) this appears to be even more common.
There are, of course, significant limitations to this study. The data was collected by an online survey shared on social media. This obviously represents a subset of the pet owning population, and it is particularly easy for passionate advocates of one extreme or uncommon type of diet or another to promote the survey and create the false impression that their views are more widespread or popular than they really are. Advocates of unconventional diets or medical approaches always seek to gain legitimacy by exaggerating the popularity of their views (despite the fact that popularity isn’t a measure of truth or scientific merit anyway).
However, it is worth considering that this study might reflect at least some real growth in the popularity of unconventional diets, including raw foods. This possibility has to be taken seriously given that such diets, and the unscientific reasoning or distrust of mainstream scientific evidence and opinion that often lies behind them, represent a real threat to animal health. In the absence of any reliable evidence for health benefits from such diets, the risks are clearly not worth taking, and any evidence that this message is not being heard or understood by pet owners should motivate veterinarians and proponents of science-based nutrition to work harder at educating the public about the risks and benefits of various feeding options.
The subject of vaccination is one of the most common, and sadly most controversial topics I address on this blog. As I have said many times, vaccines have both risks and benefits, and the balance between these must be assessed in the context of the risk of specific diseases, the scientific evidence concerning specific vaccines, and the health and needs of individual patients. The available evidence is overwhelming that vaccines do far more good than harm for most pets, and following the most recent, evidence-based guidelines is almost always the right choice for most pets.
However, fears of vaccines that are out of proportion to the real risks are widespread, and unfortunately there are some veterinarians who encourage such fears. These doctors rely mostly on anecdote to support their anti-vaccine claims, but some do cite scientific evidence (accurately or, more often, inaccurately) to make their case. Some critics of standard vaccine practices even attempt to produce their own research evidence to support their approach. This research frequently has flaws or limitations which make it not particularly reliable or illuminating.
One example I have discussed in the past is a study by Dr. Jean Dodds, a noted proponent of various kinds of pseudoscience, from raw diets to unreliable lab tests. She published a study challenging common vaccine practice in 2016 in the Journal of the American Holistic Veterinary Medicine Association (JAHVMA), a niche journal dedicated to pseudoscience. This study purported to show that small dogs could be fully immunized, and would have fewer adverse effects from vaccines, if given half of the usual 1mL quantity of most vaccines. In reality, the study was of such poor quality that it showed nothing of the kind and really provided no useful information, merely the illusion of evidence to support Dr. Dodds’ personal beliefs.
Dr. Dodds has now published another vaccine study, in concert with a couple of academic vaccine researchers and a lay person who advocates for limiting vaccination because she believes her personal dog developed cancer because of a vaccine. This study has received a lot of press coverage, associated largely with efforts to raise money to fund it and with advocacy efforts to restrict rabies vaccination. It has been in progress since 2008, and the results have been eagerly awaited not only by vaccine critics but by vaccination proponents such as myself hoping for some useful evidence to help guide our rabies vaccine practices. Unfortunately, once again the study has limitations that render the results of very little use.
Dodds WJ, Larson LJ, Christine KL, Schultz RD. Duration of immunity after rabies vaccination in dogs: The Rabies Challenge Fund research study. Can J Vet Res. 2020;84(2):153-158.
The stated purpose of this study was to demonstrate that the duration of protection from rabies vaccination is far longer than the three years most vaccines are proven to be effective and to provide support for changing legal rabies vaccination requirements and common veterinary practices. While there are potential risks to rabies vaccination, as for all effective medical therapies, these are rarely common or serious, and there is yet no real evidence that extending the interval beyond three years will reduce the risks meaningfully without also increasing the risk of rabies for some dogs.
Nevertheless, it is always useful to get additional high-quality research evidence to help guide clinical practice, so this study could have been useful. From a logistical and ethical perspective, studies looking at the effectiveness of rabies vaccine are difficult because you have to expose some dogs to certain death and others to the risk of death from this fatal disease in order to test the protection offered by vaccines. That was done in this study, but it ended up adding only very little useful information to discussions of rabies vaccination practices.
The study initially included 100 dogs, a huge number by veterinary standards. However, 35 of the dogs were not used at all, and only 35 were part of the challenge study directly testing the duration of protection provided by rabies vaccination. These were divided into several groups given different vaccines and tested for protection at different times.
Vaccine A This was killed, adjuvanted vaccine of the type commonly used for dogs (though the specific vaccine is no longer manufactured). Dogs were vaccinated at 12 weeks of age and again at 15 weeks of age. This is not a standard or recommended protocol used commonly in practice. Most dogs are vaccinated once at 12-16 weeks of age and then given a booster one year later, so this does not really reflect common practice. Presumably this was done because the dogs needed two vaccinations to be fully immunized, and the authors did not want to wait 1 year to give the booster and then have the challenge stage of the trial delayed by that year.
At 6 years and 10 months after the initial vaccination, the vaccinated dogs were exposed to rabies, as were 5 unvaccinated dogs in the control group. The USDA standard for proving a rabies vaccine good enough for use is that it must porrect at least 88% of vaccinated dogs. In this trial, all 5 dogs survived the challenge. However, only 2/5 control dogs developed rabies, showing that the virus used for the test was not sufficiently active (natural rabies infection kills 100% of infected animals). Therefore, these results can’t tell us if the test dogs were truly protected at this time point.
At 8 years after final vaccination, another challenge was done with 5 vaccinated and 5 unvaccinated dogs. This time, all of the unvaccinated dogs died, showing the test virus was active. However, all but one (4/5 or 80%) of the vaccinated dogs also died, so at this time the vaccinated dogs were no longer adequately protected.
The investigators also looked at whether or not vaccinated dogs could generate an appropriate antibody response to a booster vaccine given 6 years and 1 month after initial vaccination. None of the dogs had an antibody titer considered protective at this time (and neither did the unvaccinated dogs, of course). A booster of the same type of vaccine generated a protective antibody level by 14 days after the booster I 90% of the vaccinated dogs (and 30% of the unvaccinated controls). The authors also gave some dogs a booster using a recombinant rabies vaccine made for cats, and though this would not be done in actual practice, this also generated a protective antibody response in most dogs.
Vaccine B The authors also vaccinated several groups of dogs with another rabies vaccines, this one marketed as not containing the preservative thimerosol. This reflects Dr. Dodds antivaccine biases, since vaccine opponents often claim that thimerosol is a dangerous toxin despite the fact that it has been used extensively and shown to be safe in humans and animals for decades. This vaccine is not widely used, though apart from the missing preservative it is equivalent to common rabies vaccines.
Of the dogs vaccinated at 12 weeks and again at 15 weeks with Vaccine B, 5 were included in the initial challenge study at 5 years in which all vaccinated dogs survived but so did 60% of the unvaccinated dogs. Another 5 from this group were challenged at 6 years and 7 months after final vaccination, of which 4/5 (80%) survived. Another 12 of these dogs were challenged with rabies at 7 years and 1 month, of which 6/12 (50%) survived.
What Does It All Mean? Unfortunately, the answer is, “Not much.” The study used two rabies vaccines that are not in common use and an initial vaccination protocol that differs significantly from standard practice, so it’s not the best model for studying how rabies vaccination usually works. The numbers in each challenge group were quite small, and the death or survival of a single animal could drastically change the apparent percentage surviving or dying the challenge, so any broad generalization about the dog population in general would be unsupportable.
The first challenge studies at about 5 and 6 years can’t be interpreted since most of the unvaccinated dogs survived the virus challenge. Even though all of the vaccinated dogs lived, this doesn’t prove that we should be given rabies vaccines every 5 or 6 years instead of every 3 years. This might be an effective interval for many dogs, and there are some other sources of evidence that suggest rabies vaccine protection might often last longer than 3 years, but we still can’t say this with any confidence. Given the very severe consequences of being wrong, namely the death of many dogs and potentially of people exposed by these dogs, and the lack of evidence that extending the interval by a few years would have any meaningful benefits, this portion of the study doesn’t really provide a reason to change current recommendations.
Of the dogs challenged at about 6 ½ years, 20 percent of them died, which is more than the allowable 10-12% under the USDA guidelines, and certainly more than we should thjnk of as acceptable. In this study, that 20% was only 1/5 dogs, but in a population of millions of pet dogs vaccinated every year, that could represent a huge risk to both our pets and the human population.
This is reinforced by the portion of the study looking at antibody titers, since none of the 10 dogs tested 6 years after vaccination had a titer above the established protective level. This suggests we would be wise not to wait as long as 6 years before given rabies boosters to our dogs. Similarly, of the dogs challenged at 7 years, 50% died, so we certainly shouldn’t think of this as an acceptable interval between vaccinations.
All in all, this study undermines the claims some vaccine critics make that a single rabies vaccination is all dogs should ever need. In fact, it reinforces concerns that extending the interval between vaccines will put more dogs at risk from rabies and do more harm than good. Even if 4-5 years between boosters is as effective as 3 years, it is very unlikely this change would have any significant benefits given that the risks of rabies vaccination is very low, and considerably less than most vaccine critics suggest. An interval of 6 years or more looks very likely to increase the risk of rabies significantly based on this study.
Some vaccination critics are already suggesting that even though this study didn’t turn out the way they wanted, it still supports their general argument that we should vaccine less often than 3 years and use titers instead of vaccination. However, in the published study the authors are careful to point out that the results do not establish that a given titer level is sufficient to prove a dog is protected nor that any specific interval beyond 3 years is safe, even though they still believe this is true.
Even though I believe the risks of current rabies vaccination practices are often exaggerated, I am disappointed that the time and effort put into this study, and the dogs sacrificed as part of it, did not provide useful evidence to clarify the overall duration of immunity provided by standard vaccination practices. I also hope the authors will be vigorous in challenging the use of their work to argue for changes in rabies vaccine laws or common practice since the data do not support such changes even if the authors personally believe they are warranted.
The subject of raw diets is a constant and controversial one in veterinary medicine. The controversy stems mostly from the fact that some people are passionately committed to the idea that raw diets have health benefits, but there is no scientific evidence to support this and plenty of evidence showing uncooked food increases the risk of parasitic and infectious disease.
Just this week, there was another series of cases in which people suffered serious foodborne illness due to contact with raw pet food. This is a frequent phenomenon, and there have been many studies in the last 10 years showing raw diets present real health risks to people and pets. There is no comparable body of evidence showing any health benefits. There are, however, a few studies like this that would claim to do so:
This study comes from the DogRisk group, which I have written about previously-
This is a group of veterinarians and nutrition researchers led by Dr. Hielm-Bjorkman, a faculty member at the University of Helsinki. The organization is independent of the university, and it appears to focus on generating evidence to support raw diets, supplements, and a few other alternative health practices (such as acupuncture). The team is composed mostly of academic researchers, both vets and PhDs, working on issues of animal nutrition. Individually, they have legitimate credentials and research topics, but as a group they seem pretty dedicated to proving a set of pre-existing beliefs about raw diets rather than investigating the subject impartially.
This paper appears to fit into the group’s campaign to validate their pre-existing beliefs about raw diets. The stated goal was to evaluate potential causal factors associated with the presence of allergies in dogs, including the diet of dogs with or without allergies and the diet of the mothers of these dogs. The data come from an online survey of owners, and it is currently only available in Finnish, confining the study to a narrowly limited population not representative of pets or pet owners in other places.
Such online owner surveys are deeply unreliable. The diagnosis of allergies and the details of diet history are based entirely on the recollections and reports of pet owners, most of whom have establishes beliefs about pet health and nutrition and little or no scientific training in these subjects. Many such studies, in human and veterinary medicine, have shown that such information is often biased and not consistent with findings in more controlled research. The authors of this study actually report that almost 13% of the responses had to be discarded because they appeared to be “robot answers,” though it isn’t clear how this was determined. Clearly, this is a dubious source of data to begin with.
The authors compound the problem of reliability by imposing their own arbitrary and biased definitions on the variable they claim to be examining. They divided diet into two extreme categories: 1. A non-processed meat-based diet (NPMD) and 2. An ultra-processed carbohydrate based diet (UPCD). These are artificial categories that reflect the ideological bias of the researchers, not the reality of the kinds of foods dogs are actually fed.
“Non-processed” is meaningless unless the dogs are basically eating whole prey and plants, which it is highly unlikely many of them are doing. The term “ultra-processed” is also a value judgment that implies a negative health impact that has not actually been shown to exist in pet foods. And commercial kibble, which is likely what the authors are referring to here, is not accurately described as “carbohydrate-based.” The carbohydrate content of commercial dry diets varies dramatically, as does the type of carbohydrate (from simple sugars to complex fibers). The nutritional value and potential health effects of commercial diets will also vary greatly based on these differences, and lumping them all together in this artificial category is not a legitimate scientific research approach; it is simply a way of stacking the deck in favor of the result the authors want to get.
The authors claim they are using a validated system of nutritional categories from human nutrition science, known as the NOVA Classification. This system, however, is not meant to apply to pet foods, and the definitions of “processed” used in the system have no relationship to how pet food is prepared. Here’s what the WHO says about the NOVA classification:
A number of commonly consumed processed foods and drinks [are] certainly or probably implicated in obesity and various chronic non-communicable diseases. These include energy- dense food products, “fast foods”, “convenience foods”, soft drinks, sugary drinks, various refined starchy foods, processed meat and salt-preserved foods. [note, none of these categories is relevant to properly formulated commercial pet diets]
Food processing in itself is not the issue. One obvious reason is that nowadays, practically all food is processed in some sense and in some way. The term ‘processing’ (like the term ‘industry’) is very general and therefore not helpful, and so judgements of foods simply because they are ‘processed’ are not meaningful. Food scientists and technologists and food manufacturers are right to emphasize the benefits of originally ancient and also relatively novel processes such as drying, non-alcoholic fermentation, chilling and freezing, pasteurization, and vacuum-packing.
Confusing commercial pet diets with human convenience and snack foods because they are both produced by large industries and come in packages is misleading. The intent and formulation methods are vastly different, and the superficial similarities are not a legitimate foundation for assuming they have the same health impacts.
The NOVA classification also makes no reference to raw or uncooked meat and, in fact, states that, “These methods and processes are designed to preserve natural foods, to make them suitable for storage, or else to make them safe or edible or more pleasant to consume. Many unprocessed or minimally processed foods are prepared and cooked.”
Beginning this study with a distorted misinterpretation of terminology not intended to apply to commercial pet diets is a reflection of the underlying intent and bias behind the research. Other evidence of the authors pre-existing convictions come in the form of discussions of the “natural” diet of dogs as “carnivores” (myths used to promote raw diets which I have addressed before) and irrelevant reference to celiac disease in humans as a way to imply grains are unhealthy for dogs.
There is no apparent attempt to control for these biases in the methodology. The researchers designed the survey, defined the variables of interest, and had total freedom to create and conduct the regression analysis as they chose. It is well-established that such a lack of methodological control for bias leads to research which reflects the beliefs of the researchers more than the underlying reality of nature.
This study was also funded in part by a company selling raw dog food. Funding bias is a known problem in medical studies, and while it is not an excuse for ignoring or dismissing research out of hand, it does require methods built into the study design to limit the impact of funding source on results, which were quite limited in this study. It is also common for proponents of raw diets to claim most veterinary nutrition research is useless because it is funded by pet food companies. It will be interesting to see if this community is consistent in ignoring this paper, which supports their belief, or if they prove interested in funding bias only when it helps dismiss research they don’t agree with.
Bottom Line This study is a great illustration of ideologically motivated research. A group of scientists committed to a pre-existing belief design and conduct a study tailor-made to provide evidence supporting that belief. The authors do acknowledge some limitations to their project, but they consider them minor and accounted for, and they ignore some of the most significant problems I have mentioned here.
This study fits into a series of efforts by this same research group to validate their belief in the benefits of raw diets, and unfortunately it doesn’t contribute much to actually understanding the pros and cons of raw foods for pets because it doesn’t contain much objective, reliable evidence. It will undoubtedly be useful as marketing r propaganda for proponents of raw diets, and much like research studies done on homeopathy, it confuses rather than clarifies the issue.
This post is a bit outside the usual topics I discuss on this blog, and I have no doubt I will get angry responses and admonitions to “stay in my lane.” But at a time when America is, once again, being forced to confront our long-standing failure to deal effectively with racial inequities built into our society and institutions, I feel an obligation to address the reality that veterinary medicine is very much a part of this problem.
The facts are relatively straightforward: Over 95% of veterinarians are white in a country where about 80% of the workforce is white. Imagining this is an accident rather than the result of systemic racism is naive or disingenuous. Acknowledging an injustice is critical to rectifying it, and we cannot shy away from clearly and directly describing an unjust reality if we seriously hope to change it. Veterinary medicine is quite possibly the whitest profession in America, and this is like any problem in that we won’t be able to fix it if we don’t acknowledge it.
A common first reaction when a group of mostly white people is asked to consider the issue of racism within their community is defensiveness. There is a misconception that racism is limited to explicitly bigoted and discriminatory behavior by individuals who openly dislike people of color, and since few of us fit that caricature, it is easy to dismiss our own role in perpetuating racial inequities. However, racism is typically more insidious and systemic than this. It is not a problem of a few “bad apples” but a feature of how the barrel is built and maintained.
As an example, AAVMC data shows that the proportion of white applicants to veterinary colleges in 2016 (78.1%) was roughly the same and the proportion of white students in those colleges (78.3%). This suggests that explicit racial discrimination in admissions is not a major barrier to recruiting underserved groups into the veterinary profession. This is encouraging both because such discrimination would reflect poorly on the profession and because it would be a clear violation of federal law.
However, despite this, the representation of individuals from some underrepresented groups in both the applicant pool and as students in veterinary colleges is still dramatically lower than the proportion of the population identifying as members of these groups. For example, African Americans make up about 17% of the U.S. population but only 4.4% of applicants and 2.5% of veterinary students. The situation is actually worse than it sounds because about 70% of black veterinarians are educated at one school: Tuskegee University College of Veterinary Medicine, a historically black college. The underrepresentation of African Americans in veterinary medicine has persisted despite discussion about it and efforts to remedy it going back to the 1970s, and it is evident that there are strong and pervasive systemic factors behind this.
There have been some successes in addressing discrimination in veterinary medicine. Historically underrepresented groups have increased as a proportion of the student population.
Women, in particular, have gone from a small minority to a large minority in veterinary schools, and they are now a majority in the profession and beginning to achieve parity in some areas, such as leadership roles at veterinary schools, though there are still disparities in pay and other indicators of equity.
We have actually reached a point where the overrepresentation of women in some areas of veterinary medicine is problematic. Contrary to a common assumption, diversity is not inherently a concept intended to exclude white people or men, and true diversity in the profession requires a better balance than currently exists in the gender representation among veterinarians.
However, it is important to remember that the historic underrepresentation of women in the field was the result of both individual and systemic discrimination, and the influx of women into the profession can be seen, at least partially, as evidence of effective strategies for combatting this. The underrepresentation of men in veterinary schools today, on the other hand, seems unlikely to represent the same kind of discrimination since it is implausible that a group still in a position of privilege and power in most areas of American society would somehow be excluded by deliberate or systemic discrimination in one small domain like veterinary medicine.
There are likely complex factors involved in the decline in male applicants to veterinary schools, and many of these may involve the ways in which the profession is portrayed and perceived in the culture as well as economic factors. For example, as veterinary medicine has shifted from a focus on food and working animals to companion animals, it may be seen more as a caring or nurturing profession which cultural stereotypes classify as more appropriate for women (women are also overrepresented in pediatrics and nursing, for example). Veterinary medicine is also among the lowest-paid of the medical professions, and men may be more likely to pursue higher-paying jobs (female-dominated professions in general tend to pay less than male-dominated occupations). The growing scarcity of male role models, at least in companion animal medicine, may also be a contributing factor.
The issue of gender representation is relevant to the subject of racism in veterinary medicine both as an example of how historic discrimination can be overcome and also how complex and indirect the factors influencing the recruitment of different groups into the profession can be. The underrepresentation of African Americans in veterinary medicine, for example, is sometimes written off as a lack of interest. This narrative suggests that black people aren’t as interested in animals as white folks and so are less likely to want to be veterinarians. The issue of cultural differences in attitudes towards animals is a real and complex one, but as a facile way of denying racism as a cause for underrepresentation of African Americans in veterinary medicine, it is not convincing.
For one thing, this doesn’t explain the consistent underrepresentation of other minority groups, such as the Latinx community. The idea that multiple historically marginalized groups all just happen to not be interested in veterinary medicine is not plausible. More likely, the paucity of applicants from underrepresented groups is related to a lack of examples and role models from those communities that make the profession seem welcoming and possible for them, the disadvantages such groups face in terms of education quality and opportunity well before veterinary school, the rising cost of a veterinary medical education, and a constellation of other factors. Such factors have certainly been demonstrated to be associated with underrepresentation of African Americans, for example, in other professions, and addressing these barriers has improved diversity in these cases.
Clearly, we have a lot of work to do as a profession if we are committed to real diversity. White people must take an active part in this work, leveraging our power and privilege no support equity and improve opportunities for those who have been, and still are denied then. We must remember that diversity is not a zero-sum game in which one group must “lose” for others to succeed. No one, least of all people of color, is suggesting lowering standards or implementing some sort of active “reverse discrimination” against white people. The goal is to ensure that everyone has a chance to explore and fulfil their potential, and that barriers to this which apply disproportionally to historically marginalized groups are removed. Diversity ultimately benefits the profession and all of us in it.
As a relatively old, white, male veterinarian, I can acknowledge the injustice that has favored those like me without feeling that the effort and struggles I endured to get where I am are being invalidated. I may be good at my job, and I may have earned my place through hard work. But many people who are just as talented, just as hardworking, and who have even greater obstacles before them are as deserving but have been denied the opportunities I have had. There is no question that being white has been an advantage in my journey. It does not diminish me to acknowledge this, but it does engender a responsibility to contribute to a more just future.
Vets and vet students often get the idea that evidence-based veterinary medicine (EBVM) is a purely academic thing or isn’t practice in general practice. As a GP firmly committed to this approach, I like to debunk those myths whenever possible.
I recently spoke to the senior veterinary students at my alma mater, the University of Pennsylvania School of Veterinary Medicine about EBVM in practice, and gave some examples (including how EBVM has helped our practice in responding to COVID-19). Here are the slides for these presentations.
This an article I wrote for Veterinary Practice News about our hospital experience with the COVID-19 pandemic. Every veterinary clinic and hospital will have their own unique experience of this time, but I suspect much of this will look familiar to others in the profession and to pet owners. One element of the experience that is relevant to my work here on SkeptVet is the importance of a critical, flexible, evidence-based approach, which has helped us tremendously in dealing with the unprecedented challenge.
From the trenches: How life has changed since COVID-19 came into our lives: What veterinary medicine is like at Californina’s ground zero
The hospital is quiet as I walk in at the start of my shift. The usual bustle of clients, staff, and animals has been replaced by empty hallways and only a few masked doctors and nurses going about their work quietly, careful to keep their distance from each other. I stop at the screening table and start my day by taking my temperature. It is under 100.4 F, and I have no cough or other respiratory symptoms, which means I can work today.
I set down my belongings at my desk and go to change my clothes. I wear scrubs every day now, and I have a pair of dedicated work shoes that stay at the hospital. I also have a collection of beautiful cloth face masks sewn by one of our employees—I wear a clean one every day.
At the end of my shift, all of my work clothes go into the laundry. When I get home, everything I took to work stays in the garage. I pass quickly through the house and take a shower before I greet my family. I am especially mindful to keep my distance from my elderly mother, who lives with us, and to handle neither her dishes nor her medications. My wife does that now, since she has been working from home and hasn’t mingled with people outside the house for the last month. This is the new routine of our lives, one familiar to countless others since the arrival of COVID-19.
Operating in California’s ground zero I have worked at the same practice for 16 years. We are an unusual hospital; an independent general practice with 30 veterinarians and more than 150 other staff, open 24 hours a day seven days a week. Because we are located in Silicon Valley, an affluent area in Santa Clara County, Calif., we able to offer services not always found in first-opinion practices, such as orthopedic surgery, in-house ultrasound, cancer therapy, and advanced emergency and intensive care. Our location, however, also means we are in the center of California’s novel coronavirus outbreak. COVID-19 has changed not only my morning routine, but nearly every aspect of the work and lives of our practice, staff, and clients.
Santa Clara identified the first case of COVID-19 in the county (and the ninth in the U.S.) in early February. A sentinel surveillance study in early March confirmed community spread was already occurring, and the county began instituting social distancing measures on March 11. Initially, these involved closure of some public businesses and recommendations for people to avoid large gatherings. By March 16, Santa Clara and surrounding counties had issued shelter-in-place orders, essentially banning people from leaving home except for specified essential activities. On March 30, further restrictions were added and the shelter order was extended into May.
This rapidly expanding public health crisis and frequent changes in restrictions on public activity has presented a tremendous challenge to our hospital. We see hundreds of patients and have dozens of doctors and nurses in the building every day. We also operate on an open hospital model, meaning clients can stay with their pets for nearly every aspect of their care, from being present for outpatient procedures, to watching surgeries, to sitting with hospitalized patients as long as they choose during daytime hours. While this model is unfamiliar and startling to many in the veterinary profession, it has been an intrinsic component to our practice culture for decades. Having clients present throughout the hospital is something we, and our clients, have come to expect.
Doing things differently The coronavirus outbreak and the public health directives aimed at combating it have forced us to reevaluate our models for patient care, client service, and personnel management; our financial structures and processes; and even our role in the larger public health landscape. Such a comprehensive reevaluation of every aspect of our work, conducted rapidly and in an ever-changing environment, has been challenging, even painful. However, it is also an opportunity to take stock of who we are as health-care providers and as a business, and to grow stronger as a result.
In addition to seeing patients, part of my job in my practice is to drive and support continuing improvement in the quality of care we provide, and to help maintain staff and patient safety. I am the designated evidence-based medicine nag, responsible for translating scientific research into useful tools and actions we can take to better care for our patients. This includes training new veterinarians; developing protocols and guidance documents; conducting clinical audits and evaluating patient outcomes; and many other quality-improvement activities.
One particular project that has proven timely was my effort last August to promote more effective hand hygiene throughout the hospital. I expanded the accessibility of hand sanitizer, put up posters throughout the hospital illustrating proper handwashing technique, and of course nagged everyone to wash their hands. Lately, some staff members have jokingly suggested I may have gone a bit overboard in trying to make my point.
Of course, despite my efforts to support a culture of proactive, science-based medicine, we could not realistically have been fully prepared for what the coronavirus pandemic has required of our practice. However, this culture has proven useful in making the many adjustments necessitated by the virus in the face of limited evidence and great uncertainty. We already had a system for identifying reliable sources of information and translating imperfect science into clinical practices. Our doctors, staff, and management were long accustomed to incorporating scientific data into their daily activities and to adjusting their work routines based on changes in the available evidence. The habits of flexible, pragmatic evidence-based medicine have served us well.
The specific changes we have made in how we handle clients and patients, how we protect staff, and how we have adjusted our business to cope with the legal and economic realities of the pandemic may or may not be useful to other practices in other contexts. However, they illustrate how the methods and habits of evidence-based medicine can help a veterinary practice respond to an unexpected and unfamiliar crisis.
Applying evidence-based medicine We began our response to the pandemic by developing and collecting policy documents in one central location. With a rapidly changing environment, and frequent adjustments to policies and procedures, it was crucial the most current protocols be readily available to everyone on staff. Protocols were developed by a group representing all the teams within the practice, including doctors, technicians, and management. Input was sought from as many people as practicable, which frequently helped to identify oversights and errors, as well as to generate the widest possible array of ideas and options.
Although veterinary practices are considered essential services in our region, and therefore allowed to operate despite the restrictions of public health orders, we realized early we would need to limit our work to urgent and emergent cases, and to defer most elective and well-pet services to reduce traffic through the hospital and exposure risk to staff and clients. We developed a triage tool to help staff decide which services qualified as essential and which would need to be deferred. This was similar to the tools developed by the British Small Animal Veterinary Association (BSAVA) and other veterinary organizations.
Our initial strategy for reducing exposure risk was to screen both staff and clients for relevant clinical symptoms and for fever. Though this strategy is imperfect, it has been utilized and found helpful for identifying COVID-19 cases in some circumstances. We also set up social distancing guidelines within the hospital.
However, we quickly realized these measures were insufficient, and we made the difficult decision to ban all clients from the hospital, apart from exceptional circumstances such as euthanasia and critical acute emergencies. Clients now wait in their cars, and nurses in appropriate personal protective equipment (PPE) triage pets outside and then bring them into the hospital. All subsequent communication with clients is by telephone until the pet is returned to them outside.
This has been especially difficult for us, and for our clients, as it conflicts with our culture as an open hospital. Being separated from a sick pet is an unfamiliar experience and an added stress for clients who, like all of us, are already dealing with the impact of the pandemic in their personal lives. Most clients have been understanding of our goals in protecting them and our staff, but in the short-term, this has been one of the most uncomfortable consequences of the outbreak. The long-term effects on our culture and relationships with the community are a source of concern for all of us.
Watching out for one another Having restricted client access to the facility, the greatest risk to our own health became each other. It is often impractical to maintain effective physical distancing when working together treating patients. In response to this risk, we have continued screening staff for symptoms and fever, and we have done what we can to keep people apart in the workplace. The extra hand sanitizer I ordered in September and the handwashing protocols I posted have turned out to be quite useful! We have also had many lively discussions about the use of masks as a tool for reducing the risk of coronavirus transmission within the hospital.
The evidence concerning the value of masks in reducing spread of respiratory viruses is limited and contradictory (e.g.1, 2, 3). It seems unlikely they protect the wearer from exposure, and they can actually increase risk if improperly used. However, wearing masks may reduce the risk of an infected person from spreading the virus, particularly since asymptomatic shedding apparently occurs commonly. It is also important to remember PPE is in short supply, and the risk and needs faced by human health-care providers are much greater than ours.
Ultimately, the mask debate was settled for us by a directive from public health officials recommending the use of cloth masks in addition to physical distancing methods in businesses still operating. We are fortunate to have several employees with handicraft skills who have been making beautiful and functional cloth masks for our staff and their families. These employees have had plenty of time for such projects, as another necessary response to the pandemic has been to reduce staff in the hospital and to decrease payroll expenses.
The limitation of cases to urgent and emergent care has dramatically reduced revenue at our hospital. Veterinary small animal medicine is an unusual hybrid, being both a health-care industry and also, in many cases, a small business enterprise. Large-scale corporate ownership and consolidation of veterinary practices is certainly widespread and growing. However, the average small animal practice in the U.S. employs only two veterinarians and three to five veterinary technicians (2019 AVMA economic report). Though my practice is unusually large, we are still a much smaller business than most human health-care providers.
The drop in revenue, as well as the need to reduce the risk of coronavirus spread between employees, has necessitated dramatic cutbacks in staffing at our hospital. These reductions have involved unpaid leave, furlough, and various mechanisms dictated by the financial and regulatory environment in which we operate. Most doctors, myself included, now work one week and are furloughed for one week. Other staff members are limited in the number of shifts they can work in a month. So far, we have managed to avoid laying off any employees, but the threat to our livelihood adds to the stress imposed by the risk to our health.
Overcoming disruption As in veterinary practices around the world, our employees are struggling to face not only restrictions on their movement and activities, cancellation of planned events, closure of schools and loss of childcare, and other disruptions in their personal lives, but also a loss of income and of the security and purpose of their jobs, which for many are as much a vocation as an occupation.
Like many in the developed world facing isolation and uncertainty due to the pandemic, the role of virtual communication in our lives and businesses has expanded greatly. We have a dedicated private Facebook community for staff that has provided great support for many of us during the days we cannot work. We are, in some ways, closer than ever since we are learning more about each other’s homes and hobbies, partners and pets through this virtual community.
We are also making use of online communication tools as a hospital. In April 2019, we began offering video visits for clients. These have been a useful way of triaging patients and managing minor health problems that do not necessarily require an office visit. As a result, we had a reliable system and experienced telemedicine staff in place when the pandemic began. Since the outbreak began, the U.S. Food and Drug Administration (FDA) has relaxed requirements for a veterinarian-client-patient relationship to facilitate such use of telemedicine tools. We now have two full-time telemedicine doctors, and this has proven an excellent means of maintaining contact with clients and preserving revenue, while reducing hospital visits and exposure risk to employees and pet owners.
Since the beginning of the pandemic, our clients and staff have had questions about the risk of infection to our patients and the potential for pets to spread the virus to humans. Despite the enormous, unprecedented scientific research effort targeting COVID-19, there is surprisingly little evidence to help answer these questions.
Very few studies have specifically evaluated the susceptibility of companion animals to SARS-CoV-2 or the risk for transmission from dogs and cats to their owners or veterinary personnel. Individual case reports and limited research evidence suggest dogs are very resistant to infection and illness (4, 5, 6). Cats and ferrets appear to be more susceptible, but the risk of transmission to humans is still considered low (6, 7, 8, 9). There is essentially no research evaluating the potential for pets to act as fomites or mechanical vectors for COVID-19 (10).
We have developed guidelines in our hospital for handling pets from known COVID-19-positive households, both those with or without symptoms, and there are a number of such guidelines available from veterinary organizations (11). However, all of these are based on extremely limited evidence, and it will be some time before we fully understand what risk, if any, pets may pose to veterinary professionals or the public. This is an example of the common, but necessary challenge of practicing evidence-based medicine when data is sparse. The key is to be aware of the evidence that exists and its limitations, to take pragmatic and proportional action based on what the research says, and to be flexible and prepared to change our practices as the evidence develops.
There is reason to believe all the effort and sacrifices we have made as a hospital, as well as that of government agencies, businesses, and individuals in our area, have been effective. Though Santa Clara County was one of the first centers of community spread of SARS-CoV-2 in the U.S., cases have not grown as fast here as in some other places, and the health-care system has so far been able to cope well with the number of COVID-19 patients (12, 13). We appear to be “flattening the curve,” a rather dry and abstract phrase that represents a meaningful reduction in human suffering.
As a hospital, we have been fortunate to not yet have any known cases of COVID-19 among our staff. However, the reality is that it is only a matter of time before someone we know is infected, or falls ill, or perhaps even dies as a result of this disease. The mitigation measures we have taken and have been imposed throughout our area and around the world are not sustainable in the long term. With a highly virulent virus spreading through a completely naïve population, no proven effective treatment, and a vaccine well over a year away by some estimates, the disruption this disease has brought to our hospital and our lives will persist and evolve for a long time to come.
However, we have also learned a great deal about our capabilities as individuals and as an organization. We have been reminded of the value of creating an adaptive, science-based practice culture and of the habits and methods of evidence-based medicine. We have learned from the ways in which we were prepared to cope with this unexpected crisis, and from the ways in which we weren’t. COVID-19 has reminded us of the essential nature of veterinary medicine, not only in companion animal health and food safety, but in human health as well. It would be difficult to find a more dramatic validation of the One Health concept than our current situation.
The months ahead, perhaps even years, will continue to be challenging because of this virus, but we have tools and knowledge not available during the last century that have allowed us to respond more quickly and effectively, and this has made a very real difference in the lives of millions of people. We can and should do better in the future at preventing, predicting, and responding to such public health threats, and with the lessons learned now, I have no doubt we will. My hope is that as a hospital community and as a profession, we will emerge from this crisis stronger, smarter, and better equipped to face such challenges in the future.
John Oliver has often taken on anti-vaccine nonsense and pseudoscience of various kinds. His latest show provides a great takedown of some of the burgeoning myths and misinformation about SARS-CoV2 and COVID-19.
A reader recently asked me to take another look at a product for producing and administering platelet rich plasma (PRP). This is a subject I haven’t covered since 2013, when I wrote about a small study looking at the use of PRP for arthritis in dogs. Since that time, there has been a huge increase in the amount of laboratory and human-focused research into the use of platelets as a form of “regenerative medicine.” Much like stem cells, which I have written about more often, PRP is used to treat a wide range of conditions, such as arthritis, connective tissue injuries, wounds, and many others. Like stem cell therapies, there is a plausible rationale for PRP and some encouraging pre-clinical research, but the marketing and use of both approaches have outpaced the clinical research by quite a bit.
The basic principle is that platelets, and other components of blood, contain growth factors, compounds that reduce inflammation, and a host of other agents that could be useful in managing pain and in promoting healing. Studies looking at PRP and some of these components certainly find evidence of physiologic activity that might, in principle, be beneficial to patients. Anyone who has followed this blog or read my book, however, will know that such laboratory studies frequently fail to accurately predict what will happen in the real world of the clinic. Living patients are much more complex and varied than tissue in a test tube, and studies in rats or human cell culture don’t always reflect what happens in living dogs and cats.
The actual clinical research on PRP in veterinary species is sparse and not robust. The best evidence is in horses, and here is the conclusion of a systematic review of some of this research (for treatment of musculoskeletal lesions):
Most experimental studies revealed positive effects of PRP. Although the majority of equine clinical studies yielded positive results, the human clinical trials’ results failed to corroborate these findings. In both species, beneficial results were more frequently observed in studies with a high risk of bias. The use of PRP in musculoskeletal lesions, although safe and promising, has still not shown strong evidence in clinical scenarios.
There are a handful of clinical studies in dogs:
Prostatic cysts– This was an uncontrolled study. Ten dogs had their cysts injected with PRP, and eventually they all resolved, but there was no comparison with other treatment or no treatment, so the significance of this in uncertain.
Corneal ulcers– This was a randomized, controlled trial adding PRP to conventional therapy for uncomplicated corneal ulcers. No difference was seen in healing between the groups.
Supraspinatus tendinopathy-Another uncontrolled study in which ten dogs were treated and some got better while others didn’t. No real conclusion can be drawn from this.
Wound healing– This was a small study using three dogs. Eight small (6mm) wounds were created on each dog, and some were treated with PRP while others were not. The authors reported faster healing in the PRP-treated wounds, but there was no blinding, and the assessment of the wounds was subjective, so risk of bias is high.
Skin flaps-Another lab study in beagles. Here skin flaps were created on both sides of several dogs, one treated with PRPR and the other not. Some measures of wound healing differed between the treatments and others did not, though the difference in survival of the flaps was pretty large. Again, no blinding was involved, so the risk of bias is high.
Bone healing-Some more poor beagles had bone screws placed and some were treated with PRP while others were not. No difference in bone healing was seen.
Bone Healing-This time, dogs had a defect surgically created in their radius and then fixed in place, and healing was compared between dogs treated with PRP or untreated. There was a difference in bone healing between the groups, and again some controls for bias were missing. Other lab studies in animals looking at bone healing have found some evidence of benefits, but the conclusions are tentative due to the paucity of studies.
The growing development and use of PRP preparations in wound healing and tissue repair in people will require the development of new randomized controlled studies with large sample sizes to establish therapeutic efficacy.
Unsurprisingly, there is even less research on PRP in cats, and no conclusions at all can be drawn about the effectiveness of PRP in this species.
As usual, when the veterinary research is limited, we turn to studies in humans to see whether a therapy is likely to be helpful. While the quantity and quality of human research is inevitably higher than that in dogs and cats, the results cannot reliably be assumed to apply to other species, so such studies can only suggest, not prove the potential benefits of PRP in veterinary patients.
The human clinical trial research is vast, with almost 300 systematic reviews currently listed on Pubmed. The conclusions of these reviews are varied, with some claiming proven benefits while others suggest more research is needed for reliable conclusions or that PRP is not helpful for the condition being evaluated. And many of these reviews apply to conditions that are not relevant to veterinary species.
I have collected below a sample of the more recent systematic reviews in conditions that might be a target for PRP therapy in veterinary species. This is not an exhaustive list, merely a sample illustrating the variety of conclusions reached about the meaning of the human clinical trial literature.
PRP is a plausible therapy, and there is reason to believe it could be helpful for veterinary patients with arthritis, connective tissue and muscle injuries, wounds, and other conditions. However, the clinical trial in humans is encouraging but not consistently positive, and there is very little clinical research in veterinary species. Much of the veterinary research consists of small studies with significant methodological limitations, which means we cannot confidently conclude what conditions, if any, might benefit from treatment with PRP.
As with many veterinary therapies that are insufficiently tested, PRP involves a variety of commercial products which vary in ways which might be significant for their effectiveness but which haven’t been specifically tested in most, if any, of the conditions for which they are marketed.
Few significant signs of harm have been seen in the preliminary PRP research, so risks are likely small, though our confidence in this conclusion must also be limited by the absence of strong research evidence.
Systematic Reviews of Clinical Trials in Humans
Osteoarthritis– Regardless of the positive results obtained in several studies, it is important to take into consideration that many of the referred studies were not randomized and/or blinded controlled trials[11,88,114] and therefore should be regarded with caution. In fact, in a recent meta-analysis, from 10 manuscripts selected for the study, presented high risk of bias . The high heterogeneity among studies is another critical limitation of PRP . In addition, many of these studies suggest that autologous PRP is a safe treatment; however, the potentially negative effects of PRP were not fully investigated at this point.
Acute Muscle Injury The promising biological rationale, the positive preclinical findings, and the successful early clinical experience of PRP injections are not confirmed by the recent high-level RCTs. Therefore any benefit in terms of pain, function, return to sport, and recurrence using PRP injections for the treatment of acute muscle injuries is not supported. Due to the bias in the studies, the heterogeneity of the findings, and the limited sample size, the evidence should be considered to be of low or very low quality.
TMJ Osteoarthritis- There is slight evidence for the potential benefits of intra-articular injections of PRP in patients with TMJ-OA. However, a standardized protocol for PRP preparation and application needs to be established.
Orthopedics- The results of this meta-analysis, which documents the very marginal effectiveness of PRP compared to controls, does not support the use of PRP as conservative treatment in orthopaedics.
Knee osteoarthritis- Intra-articular PRP injections probably are more efficacious in the treatment of knee OA in terms of pain relief and self-reported function improvement at 3, 6 and 12 months follow-up, compared with other injections, including saline placebo, HA, ozone, and corticosteroids.
Knee osteoarthritis- In patients with symptomatic knee OA, PRP injection results in significant clinical improvements up to 12 months post injection. Clinical outcomes and WOMAC scores are significantly better after PRP versus HA at 3 to 12 months post injection. There is limited evidence for comparing leukocyte-rich versus leukocyte-poor PRP or PRP versus steroids in this study.
Rotator Cuff Injury- The results of this meta-analysis do not support the use of platelet-rich plasma/platelet-rich fibrin matrix in patients with rotator cuff injuries.
Knee osteoarthritis- On the basis of the current evidence, PRP injections reduced pain more effectively than did placebo injections in OA of the knee (level of evidence: limited due to a high risk of bias). This significant effect on pain was also seen when PRP injections were compared with hyaluronic acid injections (level of evidence: moderate due to a generally high risk of bias). Additionally, function improved significantly more when PRP injections were compared with controls (limited to moderate evidence). More large randomised studies of good quality and low risk of bias are needed to test whether PRP injections should be a routine part of management of patients with OA of the knee.
Knee OA- PRP intra-articular injection of the knee may be an effective alternative treatment for knee OA, especially in patients with mild knee OA. Although some studies suggested that the effect of PRP was no better than HA, we found that it was no worse. A large, multicenter, randomized trial is needed to further assess the efficacy of PRP treatment for patients with knee OA.
Hip OA- Literature to date concludes that intra-articular platelet-rich plasma injections of the hip, performed under ultrasound guidance to treat hip osteoarthritis, are well tolerated and potentially efficacious in delivering long-term and clinically significant pain reduction and functional improvement in patients with hip osteoarthritis. Larger future trials including a placebo group are required to further evaluate these promising results. Level of evidence: Level I, a systematic review of level I studies.
Knee OA- This systematic review demonstrated no long-term statistically significant improvement in patient validated outcomes and secondary outcomes both in patients with knee OA or following TKA for OA. However PRP has been shown to have short to medium-term benefits in pain control after TKA and activities of daily living in patients with OA.
Tendinopathy– There is good evidence to support the use of a single injection of LR-PRP under ultrasound guidance in tendinopathy. Both the preparation and intratendinous injection technique of PRP appear to be of great clinical significance.
OA Pain- Although the results of the included studies showed that arthrocentesis or arthroscopy with PRP or PRGF, saline, or HA injections all reduced pain and increased mouth opening, the evidence was of very low quality. Further studies are needed to confirm these preliminary results showing that PRP or PRGF with arthrocentesis or arthroscopy significantly improved pain but did not increase MMO compared with findings in the control or HA groups.
Knee OA- IA-PRP is a viable treatment for knee OA and has the potential to lead to symptomatic relief for up to 12 months. There appears to be an increased risk of local adverse reactions after multiple PRP injections. IA-PRP offers better symptomatic relief to patients with early knee degenerative changes, and its use should be considered in patients with knee OA.
Lateral Epicondylitis- The current best available evidence suggests that CSI improves functional outcomes and pain relief in the short term, while AB and PRP are the most effective treatments in the intermediate term.
Degenerative joint disease- The analysis showed an increasing number of published studies over time. Preclinical evidence supports the use of PRP injections that might promote a favourable environment for joint tissues healing. Only a few high-quality clinical trials have been published, which showed a clinical improvement limited over time and mainly documented in younger patients not affected by advanced knee degeneration.
Achilles tendinopathy- The main finding of this study was the paucity of high-level literature regarding the application of PRP in the management of patellar and Achilles tendinopathy. However, the clinical data currently available, although not univocal, suggest considering PRP as a therapeutic option for recalcitrant patellar and Achilles tendinopathies.
Muscle Strain- Evidence from the current literature, although limited, suggests that the use of PRP may result in an earlier return to sport among patients with acute grade I or II muscle strains without significantly increasing the risk of reinjury at 6 months of follow-up. However, no difference in time to return to sport was revealed when specifically evaluating those with a grade I or II hamstring muscle strain.
Rotator Cuff- The currently limited available evidence on PRP for nonoperative treatment of chronic rotator cuff disease suggests that in the short term, PRP injections may not be beneficial. When directly compared with exercise therapy, PRP does not result in superior functional outcomes, pain scores, or range of motion. However, interpretation of this literature is confounded by the lack of reporting of the cytology and characteristics of PRP.
After knee replacement- Current meta-analysis indicates that PRP is associated with increasing the ROM after TKA in short term and long term. What’s more, PRP can also decrease the WOMAC score and pain intensity without increasing the occurrence of infection.
Patellar tendinopathy- Platelet-rich plasma is a safe and promising therapy in the treatment of recalcitrant PT. However, its superiority over other treatments such as physical therapy remains unproven. Further RCTs are required to determine the relative effectiveness of the many available treatments for PT and to determine the subgroups of patients who stand to gain the most from the use of these therapies.
Lateral epicondylitis- Corticosteroid injections provide rapid therapeutic effect in the short-term with recurrence of symptoms afterwards, compared to the relatively slower but longer-term effect of platelet-rich plasma.
Lateral epicondylitis- Local corticosteroid injections demonstrated favorable outcomes compared with those of local PRP treatments for lateral elbow epicondylitis during the short-term follow-up period (4 weeks and 8 weeks post-treatment). Otherwise, at the long-term follow-up (24 weeks post-treatment), PRP injections had improved pain and function more effectively than corticosteroid injections.
Knee OA- PRP intra-articular injections of the knee may be an effective alternative treatment for knee OA. However, current studies are at best inconclusive regarding the efficacy of the PRP treatment. A large, multicenter randomized trial study is needed to further assess the efficacy of PRP treatment for patients with knee OA.
Knee OA- In short-term outcomes (?1 year), PRP injection has improved functional outcomes (WOMAC total scores, IKDC score and EQ-VAS) when compared to HA and placebo, but has no statistically significant difference in adverse events when compared to HA and placebo. This study suggests that PRP injection is more efficacious than HA injection and placebo in reducing symptoms and improving function and quality of life. It has the potential to be the treatment of choice in patients with mild-to-moderate OA of the knee who have not responded to conventional treatment.
Epicondylitis, Plantar fasciitis- The use of PRP yields statistically and clinically better improvement in long-term pain than does CS in the treatment of EE. The use of PRP yields statistically and clinically better long-term functional improvement than that of CS in the treatment of PF.
Tendinopathy- Although the results of this review show promise for the use of PRP in chronic tendinopathy, the analysis highlighted the need for more controlled clinical trials comparing PRP with placebo.
Hamstring injury- Meta-analysis showed superior efficacy for rehabilitation exercises. PRP injection had no effect on acute hamstring injury. Limited evidence was found that agility and trunk stabilisation may reduce re-injury rates. The limitations identified in the majority of RCTs should improve the design of new hamstring RCTs.
TMJ OA- This meta-analysis demonstrated that PRP injection provided adjuvant efficacy to arthrocentesis or arthroscopy in pain reduction for temporomandibular joint osteoarthritis in the long term. Furthermore, PRP injection significantly reduced pain better compared with HA injection, saline injection, or no injection.
Knee OA- The results of this systematic review and meta-analysis suggest that PRP is superior to HA for symptomatic knee pain at 6 and 12 months. ACP appears to be clearly superior over HA for pain at both 6 and 12 months. There were no advantages of PRP over HA for clinical outcomes at both 6 and 12 months.
I haver written about pulsed-electromagnetic field devices (PEMF) a couple of times before (1, 2). In my most recent review, I concluded:
Despite the fact that there has been interest in the potential medical applications of electricity for over 150 years, and serious scientific research investigating PEMF has been going on for over 50 years, there is surprisingly little robust evidence showing meaningful clinical benefits…PEMF devices are widely used, and this creates the impression that they have been solidly validated, but the reality is more ambiguous…There are very few clinical trials of PEMF in [veterinary] patients. The studies that have been published have not found consistent and convincing evidence of clinically meaningful benefits…The marketing claims of PEMF manufacturers and the excitement of proponents far exceed the strength of the available scientific evidence.
Unfortunately, the lack of evidence is seldom a barrier to aggressive marketing of therapies in veterinary medicine, and this is certainly true for PEMF. What is perhaps more frustrating, is that companies often support or produce small studies with significant limitations as evidence to promote particular uses. These studies are rarely followed, as they should be, by larger, better trials that could be used to justify actual clinical use.
This certainly appears to be the case for the most well-known veterinary PEMF device, the Assissi Loop. Rather than following up the tentative studies I reviewed for pain, the company has decided to generate yet more weak evidence to justify marketing their device for yet another indication, this time separation anxiety. Their marketing materials are a classic example of claims that go far beyond anything justified by the actual scientific evidence:
“The solution” is bad enough, but there had better be some pretty solid clinical research to justify “returns the anxious brain to a more balanced emotional state with long-lasting effects” and “proven to work alone without other treatments or training!” I can’t wait to see the large, robust, long-term clinical trial that shows the Assissi Loop is ready to replace all other separation anxiety therapies and vanquish the disease for ever! So where is it? What? There is no such study?
To call what the company offers as evidence for these dramatic claims underwhelming would be a dramatic understatement. An open-label study lasting six weeks in nine dogs. That’s it! No placebo control, no blinding, no peer-reviewed publication (only a conference report), and a lead investigator who also happens to be the Chief Business Officer of the company selling the product. A pilot trial like this is laden with uncontrolled bias and error, and while it might be enough to justify a real controlled study, it is not even close to sufficient evidence to support the wild marketing claims made for the product.
I would be thrilled to see a treatment with no detectable adverse effects that could improve or even cure separation anxiety in the vast majority of dogs with 15 minutes of treatment twice a day for six weeks. That would be a miracle, and I would be glad to see it. However, the evidence threshold for miracles in medicine is pretty high, and this study isn’t even close to that threshold. It seems to me inappropriate to make such dramatic promises based on such thin evidence, and it would be more useful for companies such as this to put their resources into supporting rigorous, independent testing of existing claims rather than looking for new markets to create with still more small, limited “pilot” trials.
Over the years, one of the most common subjects I have discussed on this blog is vaccination, including their risks and benefits and how pet owners can evaluate them to decide which vaccines are appropriate to give their pets. This is a far more complicated subject than many opponents of vaccination claim.
It is clear that vaccines, like any medical therapy, can cause harm. However, the evidence for specific types of harm is often poor, and the anxiety about vaccination is often based on fear, not real scientific evidence of real risks. Claims that vaccines cause autoimmune disease (1, 2 or behavioral problems, anxieties about “toxins” such as mercury in vaccines, claims that lower “doses” of vaccines are safer than standard volumes (1, 2), and the value of antibody titers as substitutes for vaccination are all subjects I’ve addressed here. There are few simple, absolute answers, but it is clear that the benefits of vaccination almost always outweigh the risks. However, the anti-vaccine movement is alive and well in veterinary medicine, and vaccine opponents have been all too effective at taking the reasonable concerns pet owners may have about vaccine safety and turning them into unreasonable fear.
In human medicine, we have seen the serious consequences of this fear. Vaccine-preventable diseases are making a comeback, and children are being harmed and killed by illnesses they should never have been allowed to contract. The World Health Organization has listed vaccine hesitancy as one of the top ten public health threats we face. One major element to the growing public health threat of vaccine refusal has been the use of exemptions from vaccine requirements for children attending public schools. While there are uncommon medical reasons to avoid vaccinating some children, exemptions based on the religious or personal belief of parents have reduced vaccine coverage and placed all children at greater risk, those who cannot or will not be vaccinated and even those who are, since vaccine protection is excellent but never perfect.
In California, non-medical exemptions were prohibited by law in an effort to better protect public health. Unfortunately, anti-vaccine activists were able to undermine the law by seeking exemptions from deluded or unscrupulous physicianswilling to grant exemptions without legitimate medical and scientific foundations. This loophole had to be addressed in additional legislation giving the state health department authority to review medical exemptions when an excessive number of them are issued by an individual doctor or if a specific school has an excessively low vaccine compliance rate. This is an imperfect solution, but the original law has improved vaccination rates in the state, and it is likely the new measures will be somewhat helpful in reducing the risk posed by individual anti-vaccine activists.
In veterinary medicine, most vaccinations are not legally required for most pets. Vaccination rates are lower, and the occurrence of vaccine-preventable disease are consequently higher, than they should be, but the law considers pets to be property, so there is no real movement to require vaccination even if it is clearly in the best interests of the animals. The exception to this is immunization against rabies, which is often required at the state or local level in pets (almost always in dogs, and sometimes in cats and ferrets) because of the risk infected animals present to humans.
Rabies is almost always fatal, and tens of thousands of people worldwide are killed by it every year. Most of these are exposed by domestic dogs. This is rare in the developed world because of long-standing and successful vaccination campaigns, so many people do not adequately appreciate the danger of reduced vaccine coverage.
Medical exemptions to rabies vaccination are sometimes sought for pets with a history of adverse reactions to rabies vaccine, with conditions that might be exacerbated by vaccination such as autoimmune disease, and of course for many illegitimate reasons such as age or simply the owner’s perception that the vaccine is unsafe or not necessary. Local government often has discretion as to whether to grant such exemptions, and the process and criteria are variable and inconsistent. Anti-vaccine advocates have long wanted to reduce vaccination against rabies (and other diseases), and for the first time a state-level law has been passed which would facilitate this.
The state legislature in Delaware has passed a law allowing veterinarians to exempt individual dogs, cats, and ferrets from rabies vaccine requirements. This law is, unfortunately, a blank check to anti-vaccine vets that contains no protections against the kind of abuse and deception that has plagued efforts to improve compliance with vaccine mandates in humans. The law states:
Exemption from vaccination against rabies may be permitted if a licensed veterinarian has examined the animal and based on the veterinarian’s professional judgment, has certified in writing that at the time, vaccination would endanger the animal’s health because of its infirmity, disability, illness, or other medical considerations.
This allows complete personal discretion on the part of the veterinarian to determine whether or not a pet should be vaccinated without regard to any legitimate scientific standards. Plenty of alternative medicine vets have completely unscientific beliefs about the risks of vaccines, and these doctors will be able to exempt any pet from vaccination based solely on these beliefs. And if clients demand exemptions for reasons that are not scientifically valid, vets will undoubtedly feel pressured to grant them. There are no rules or constraints they can use as justification for denying illegitimate requests.
The law also makes reference to rabies titer testing. It has been argued that since a high rabies titer likely indicates protective immunity in most pets (some challenge testing has been done for this disease), titers could be used in lieu of vaccination in some cases. This is a reasonable argument, and if clear requirements for running and interpreting antibody titers were made, they might be an appropriate alternative to vaccination on a fixed schedule. However, this law does not address any of these issues and merely states that titers can be done, presumably however the individual veterinarian wants.
A titer test, in the case of these medical exemptions, may be administered to assist in determining the need for the vaccination.
This is entirely meaningless since it does not require a titer or define how titers should be measured or used to determine immune status. The complete lack of any input on this law by informed scientific experts in the subject is clear here.
Reasonable changes to vaccination laws based on sound science are totally appropriate. It may be that titers are an effective substitute for vaccination in some cases. However, ill-considered and sloppy laws like this driven by passionate misconceptions about vaccines can only endanger pets and humans. This law is not in the best interests of companion animals or public health, and it is sad that the true danger of such antivaccine activism and laws such as this will only be clear once pets and people start dying of rabies in the U.S. as they do in places where vaccination is not available of common.