The precise wording of definitions varies with author, but at its core, EBVM is a structured and explicit method that helps us make decisions, in clinical practice as well as the many other areas where veterinarians might work.
EBVM from EBM
Evidence-based veterinary medicine, like some other areas of veterinary medicine, has drawn upon expertise in the medical field, where applying the principles in practice has become more widely accepted. One commonly used definition of evidence-based medicine (EBM) is:
“… the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients. The practice of EBM means integrating individual clinical expertise with the best available external clinical evidence from systematic research.” (Sackett et al., 2000)
There are important differences between the practice of EBVM and EBM, including the patient-(owner)-clinician relationship, as well as the availability and quality of scientific literature; these differences affect how we approach evidence-based practice in the veterinary context, and will be explored within this tutorial.
EBVM through the years
In the 18th century, sailors died from scurvy on a regular basis. In 1747, on Her Majesty’s ship the Salisbury, young men under the care of Dr James Lind were dying, despite him following the current treatment recommendations for scurvy. At the time, the Royal College of Physicians recommended sulphuric acid, and the Admiralty recommended vinegar treatments. Dr Lind noted that the recommendations were all written by ‘experts’ who had never been on a long sea voyage.
Dr Lind elected to review the current evidence and run his own treatment trial to see if he could find a treatment for scurvy. His trial compared the success of a concoction of sulphuric acid, vinegar, nutmeg, cider and seawater to a diet of two oranges and one lemon in different groups of sailors in similar stages of disease, who were otherwise sharing the same basic diet.
The sailors receiving the citrus fruit clearly improved more quickly than those ingesting the tasty sulphuric acid concoction, and Dr Lind had some evidence for a superior treatment. Following this clinical trial, the Admiralty made lemon juice compulsory for sailors, and deaths due to scurvy declined precipitously.
Dr Lind’s study is an excellent early example of the practice of EBM. As a clinician, Dr Lind posed the right, pertinent question about the disease, reviewed the relevant current evidence (literature), recognised the limitations of that evidence and then executed a simple clinical trial which led to a change in the way he treated his patients. Dr Lind also passed on his new knowledge by telling the Admiralty and the Royal College of Physicians, who then instituted change, saving many lives at sea.
Over the last few decades, EBM has significantly impacted and, in many areas, improved patient care. There are now many initiatives in place to assist healthcare professionals in making evidence-based decisions (CEBD, 2014; CEBM, 2014; Cochrane collaboration, 2014; NICE, 2014).
Although different practitioners may define what EBVM is in different ways, it is also important to recognise what EBVM is not. EBVM is not a distinct discipline to be practised only by a few ‘EBVM specialists’ or a rule book that MUST be followed. Rather, EBVM is a method which can be incorporated into everyday practice to help inform decisions regarding individual cases (be those individual patients or herd health programs), or to design or improve practice protocols or clinical audit processes. Finally, in the words of Cockcroft and Holmes (2003), ‘EBVM is not about pursuing dogma’: EBVM is not a rigid set of steps that must be strictly adhered to, but is rather a tool for approaching clinical decisions in a methodical way, and can be adapted to suit the situation.
Many of the terms used in defining EBVM are included for a specific reason, but may also raise questions in one’s mind. For instance:
- What is meant by ‘best’ and ‘most relevant’ available evidence’?
- How do we apply correct weight to our patient’s situation as well as the owners’ goals and values?
- What weight do we put on our own clinical assessment as compared to what is in the literature?
We will seek to answer all these questions as we proceed through this tutorial – and perhaps come up with a few more! In this introductory section, we will investigate some history of EBM and EBVM, and explore some definitions.