While the idea of applying current knowledge to patient care dates back as far as medicine itself, the modern concept of evidence-based medicine (EBM) has developed in response to the ever-increasing need for clinicians to make patient care decisions in a reasoned and rational manner. It is the application of evidence gleaned from careful research, merged with clinical experience, patient values, and the unique features of every individual case, for the purpose of making the most effective patient care decisions.
It must be noted that the search for and use of the best evidence does not by itself constitute the appropriate practice of EBM: Patient care requires a more global balance of many factors, and true EBM attempts to address this. While there are general themes to an EBM approach to clinical problems, it would be a mistake to view EBM as a search for a “script” to follow in deciding how to handle a clinical presentation. EBM is not meant to exclude the individualized approach to medicine, but rather to enhance and refine it.
Perhaps the best way to think of EBM comes from McMaster University (Hamilton, Ontario, Canada), where in the 1970s the scholarly pursuit of EBM began to flourish. Researchers at McMaster describe EBM as the development of an attitude of enlightened skepticism toward the evidence behind daily clinical decisions. Clinical evidence should be viewed through the lens of epidemiologic principles, and rather than accepting all that we are told, we should require a careful evaluation of the evidence. Our patients demand the best possible care, and we owe it to ourselves, our patients, and our profession to determine the best possible care for each individual.
HOW IS EBM RELEVANT TO THE HOSPITALIST?
To make effective patient care decisions, hospitalists are no different than other clinicians. In fact, every practicing hospitalist asks and answers dozens of clinical questions each day, and many of these decisions immediately affect the well-being of patients.
For example, should an otherwise healthy 60-year-old patient receive perioperative beta-blocker therapy prior to laparoscopic cholecystectomy? What is the best way to evaluate this diabetic woman’s nonhealing leg ulcer for osteomyelitis? What is the prognosis for this young man newly diagnosed with glioblastoma multiforme?
Each of these is an example of a clinical question many of us may have already asked ourselves today. Hospital medicine moves quickly, and it is important to find the best answers to these questions as rapidly as possible. EBM provides a framework to help get to these answers and ultimately it helps us manage patients most effectively.
An additional aspect of hospitalist practice that is somewhat unique is the central role the hospitalist plays in the complete care of patients. The hospitalist is often called upon to bring specialists together for a patient’s care, and EBM can be important in ensuring that these specialists make the best decisions for the patient.
For example, a careful review of the literature suggests that low molecular weight heparin is preferable to aspirin for postoperative deep vein thrombosis prophylaxis for most hip replacement patients. If an orthopedic service nevertheless writes orders for aspirin in such a patient, the informed hospitalist would want to clarify the rationale behind this choice and if appropriate recommend the use of low molecular weight heparin instead. Thus, hospitalists may need to anticipate not only their own clinical questions but also any clinical question relevant to the care of any of their patients.
THE ELEMENTS OF EBM?
At its essence, EBM means applying the best evidence available for the benefit of patients. In this series, we will review the basic elements of EBM:
- Constructing an answerable clinical question;
- Searching for the best evidence for the question at hand;
- Critically appraising the evidence for its validity, importance, and relevance to your patient; and
- Applying the best evidence to your clinical practice.
Each of these deserves a brief comment. To find the information most relevant to a clinical question, it is helpful to have a well-defined query of appropriately narrow scope. If we
want information on perioperative beta-blockade in the scenario outlined above, it may not be helpful to apply evidence derived from vascular surgery patients over age 65 with known coronary artery disease. If information were available on outcomes in younger patients undergoing lower-risk procedures, this might be more relevant to our question. Thus, an approach to constructing effective clinical questions is a critical skill for EBM.
The best clinical question cannot help us if we don’t know how to find the evidence relating to that question, however. Therefore, EBM requires some understanding of the relative benefits of sources such as Ovid MEDLINE (www.medscape.com) or UpToDate (www.uptodate.com), in addition to how to navigate through these sources to get to the evidence. Thankfully, these databases are becoming more powerful all the time, while also working to remain user-friendly. An approach to effective searches is clearly an important skill for EBM.
Once we have found the evidence for our question, we need to know how to evaluate the quality of the evidence. There are many guides available for individual types of clinical questions, but there are consistent themes across all types of questions, including assessment for potential bias, proper interpretation of study results, and deciding whether the results can be applied to your patient. Understanding these themes and then taking the evidence back to the bedside is the culmination of the EBM process for our patients.
EBM is an approach to making patient care decisions incorporating the highest quality available evidence. This is of great relevance to hospitalists, especially given the central role hospitalists play in the care of patients across multiple disciplines. This series will serve as an introduction to the many facets of EBM, focused to a practicing hospitalist audience. TH
Dr. West practices in the Division of General Internal Medicine, Mayo Clinic College of Medicine, Rochester, Minn.