As near as anyone can tell, the term “evidence-based medicine” (EBM) was introduced to the human medical community in 1990 as the name for an effort to evaluate, and, in turn, acquire a better empirical basis for the practice of medicine. Since its introduction to human medicine– and subsequently, to veterinary medicine as evidence-based veterinary medicine (EBVM)– the definition of EBM has evolved and expanded.

Initially, the term was meant only to pertain to the quality of the evidence for a particular medical intervention, but now it also includes considerations such as the expertise of the clinician, the values, preferences, and circumstances of the patient or, as is the case in veterinary medicine, those of the caretakers.

Despite the fact studies have shown EBM improves clinical outcomes—which, after all, is the most important metric by which any treatment should be judged—misconceptions about, and barriers to, the practice of EBM persist.

These myths and misconceptions may interfere with adopting a clinical practice philosophy based on using the best available evidence. Since, at least from a patient perspective, anything that would limit the use of evidence-based practice (EBP) should be undesirable, let’s look at a few of the commonly held misbeliefs about EBVM.

1) EBVM is one-size-fits-all

A pervasive myth about EBM is the idea that evidence from systematic research is the only acceptable basis for clinical decision-making. While it is true EBM originally focused on critical appraisal, development of systematic reviews, and clinical practice guidelines, EBVM is not dogmatic, “cookbook” medicine. EBVM is (or at least should be) a collaborative process between the veterinarian and the client, focusing on the best interests of the patient. An evidence-based framework of practice acknowledges the experiences, values, and preferences of all interested parties can and should contribute to clinical decisions.

The clinician is tasked with navigating a sea of information–which, admittedly, can be a great challenge–and then deciding how best to apply it to the individual patient, with the approval of the client. The client, who is now able to become relatively armed with all sorts of “evidence,” has the right and even responsibility to participate in shared decision-making. This can sometimes result in clients acting against the thoughts of what the clinician believes is “best,” and instead selecting what is “best for them” based on how the clients value specific benefits and harms (e.g. is the treatment “natural”?).

EBM has evolved along two lines of development. It is, and always has been, about using scientific tools to find reliable answers to medical questions. However, it has also developed with the goal of providing people with information about the advantages and disadvantages of medical options so they can actively make their own decisions. Given relatively few studies meet all of the criteria that are generally agreed as making a “good” study, disagreements about the quality of evidence that comes from a particular study should be expected. Thus, it is important for people to think independently about the results of an individual study prior to applying them in the clinic.

2) Applying some evidence equals EBVM

Just about anything can be construed as evidence, from sincere anecdote to the most rigorously conducted systematic reviews. However, while just about anything is evidence, some types of evidence are clearly better than others, hence, the often-reproduced pyramid of evidence.

However, insofar as clinical decision-making goes, it is also important to look at evidence that is important to patient outcomes. Thus, while ideally, all evidence should be of the highest quality, evidence that is related to outcomes– for example, mortality, morbidity, and quality of life– is generally more important than disease-oriented evidence (e.g. physiologic variables, or blood testing) when it comes to making clinical decision. Trials comparing surrogate outcomes (e.g. blood glucose levels) may be contradictory if study populations differ, or if trials are biased (either intentionally or unintentionally).

It is simply a fact that the goals, designs, and methods of studies aimed at providing strong answers to questions about clinical practice are in some respects quite different from those of studies aimed at understanding basic mechanisms of disease.

While designed for human physicians, the Evidence-Based Medicine Toolkit is a very helpful resource for practicing clinicians who want to get better at applying the best available evidence to their patients. https://www.aafp.org/pubs/afp/authors/ebm-toolkit.html

3) There is too little time to search, and good evidence is hard to find

Evaluating relevant evidence for a particular condition is a daunting, almost insurmountable task. It is a bit unreasonable to expect practicing veterinarians can both care for animals and also aggressively sort evidence. Evidence sources, such as traditional textbooks, are difficult to update rapidly. What is known at any point in time will likely change as medical science moves forward, so in an effort to stay current, it is always best to focus on the most contemporary sources.
Fortunately, there are an increasing number of sources of pre-appraised evidence in veterinary medicine, in which teams of experts have already done some of the heavy lifting. Examples include:

• Evidence-Based Veterinary Medical Association (ebvma.org). The site includes a small animal focused list of specialty organization guidelines and consensus statements.
• RCVS Knowledge (https://veterinaryevidence.org/index.php/ve)
• University of Nottingham Centre for Evidence-Based Veterinary Medicine (https://www.nottingham.ac.uk/cevm/evidence-synthesis/evidence-synthesis.aspx )

Subscription services:

• DynaMed (http://www.dynamed.com)
• Essential Evidence Plus (http://www.essentialevidenceplus.com/)
• VetCompanion (https://vetcompanion.com/)
• VetLexicon (https://www.vetlexicon.com/) in veterinary medicine (this service is free with EBVMA membership)

4) Evidence is generally non-existent, incomplete, or conflicting, so
why bother?

It is true quality evidence is lacking in many areas of veterinary medicine, and perhaps especially so in large animal practice, where veterinarians, as well as the number of patients overall, are fewer.

When looking for guidelines, however, it is important to look for those with a low risk of bias (e.g. no ties to industry). Even if evidence is incomplete now, it is important for clinicians to keep up with the veterinary medical literature, and to be ready to change practice with changing evidence.

5) There’s too much information to draw specific evidence

The millions of articles and tens of thousands of sites containing evidence make it hard for clinicians to stay current while also making it easy for uncritical reviewers to selectively look for articles that support their
own biases.

Thus, rather than trying to always stay current on every aspect of clinical practice, clinicians would be well-served to look for evidence when questions arise about specific patients, disorders, or procedures. Trying to answer a question that is as specific as possible usually results in a relatively small number of articles that can then be rapidly reviewed and see if the articles are of sufficient quality to warrant further investigation. Day-to-day clinical practice is generally conducted based on existing knowledge and experience, and rightly so. Incorporating the best evidence into clinical practice does not require clinicians to disregard everything that they think they know, rather, it requires them to upgrade their knowledge base in response to particular clinical questions.

Conclusion

Regardless of difficulties and misconceptions, EBM has made contributions to the practice of medicine that will endure. In reality, EBM is neither the panacea nor the bugaboo that its mythology has suggested. Rather, EBM offers us a framework and a set of tools by which we can systematically improve as clinicians, colleagues, advocates, and investigators by considering clinical experience and patient preferences against a background of the highest quality scientific evidence that can be found.

The main challenge for EBM remains how to develop a coherent theory of decision-making.

EBM’s enduring contributions to clinical medicine include placing the practice of medicine on a solid scientific basis, the development of more sophisticated hierarchies of evidence, the recognition of the crucial role of patient values and preferences in clinical decision-making, and the development of the methodology for generating trustworthy recommendations.

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David Ramey, DVM, is a Los Angeles, Calif.-based equine practitioner. Dr. Ramey is also the current president of the Evidence-Based Veterinary Medicine Association (EBVMA) with different members writing this column. While all articles are reviewed for content, the opinions and conclusions of the author(s) do not necessarily reflect the views of the EBVMA or Veterinary Practice News. For information about the association or to join, visit https://www.ebvma.org/.

References

1. The history of evidence-based medicine. National Library of Medicine. https://www.ncbi.nlm.nih.gov/books/NBK390299/#:~:text=
   Evidence% 2Dbased%20medicine%3A%20Definition&text=Gordon%20Guyatt%20from%20McMaster%20University,t%22%20in%201996%20with%20colleagues. Accessed June 7, 2023
2. Imrie, R, Ramey, D. The evidence for evidence-based medicine. Complement Ther Med 2000 Jun;8(2):123-6.
3. Doig GS. Evidence-based veterinary medicine: what it is, what it isn’t and how to do it. Aust Vet J. 2003 Jul;81(7):412-5.
4. Sackett DL, Rosenberg WM, Gray JA, Haynes RB, Richardson WS. Evidence based medicine: what it is and what it isn’t. BMJ. 1996 Jan 13;312(7023):71-2.