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EBM basics

What is EBM?

The term “evidence-based medicine” (EBM) was coined in 1991 by Gordon Guyatt, a Distinguished University Professor at McMaster University in Hamilton, Canada.

The emergence of EBM marked a departure from an approach that relied heavily on physicians’ experience, opinion, and authority, with less emphasis on objectively and systematically collected verifiable scientific data from reliable sources.

As summarized by Guyatt in 1992, “Evidence-based medicine de-emphasizes intuition, unsystematic clinical experience, and pathophysiologic rationale as sufficient grounds for clinical decision making and stresses the examination of evidence from clinical research.”

In the more recent statements co-authored by Guyatt, EBM was described as clinical practice guided by rigorous summaries of the most trustworthy evidence, by patients’ values and preferences, and by clinicians who have the skills and experience to understand and communicate evidence.

How to make use of EBM?

Simply publishing data (evidence) from scientific research is not enough to guarantee such findings will provide the basis for making clinical decisions or will be considered indispensable for the decision-making process. Rather, publication alone serves as an indicator that such data may be vital and have to be considered judiciously.

Before evidence can be used in practice, it is necessary to accurately assess the clinical situation—that is, establish the diagnosis and consider available management options, which are further dependent on the health-care system (availability of investigations, medication, procedures, and so on). The individual skillset, knowledge, and experience of the physician constitute a crucial part of this process and are irreplaceable.

However, to evaluate the favorable and unfavorable outcomes of different diagnostic and treatment options the physician has to be familiar with relevant research findings—which is to say, the physician has to know how to find such data, critically appraise their trustworthiness and clinical significance, and then apply them to the individual patient’s situation. It is usually difficult for individual clinicians to go through this complete process alone.

These days, the tasks of summarizing the evidence and presenting the possible choices are frequently in the hands of teams developing clinical practice guidelines, which include clinicians and—increasingly more often—patients.

Assuming such practice guidelines are aligned with the EBM principles (and the clinician has to be able to judge that), the final step in the decision-making process is the choice of a management strategy that seems optimal in the given context and clearly includes the particular patient’s values and preferences. The choice is made together by a team consisting of the clinician and the patient.

This is the essence of the art of modern medicine and our understanding of EBM. The first principle of EBM states that, paradoxically, evidence alone is not sufficient to make decisions.

EBM principles can be applied not only to individual clinicians but extend in scope to the level of institution and entire health-care system. As such, they should be familiar to and well understood by all stakeholders responsible for the governance and financing of the system.

Selected References

  1. Guyatt G, Cairns J, Churchill D, et al. Evidence-based medicine. A new approach to teaching the practice of medicine. JAMA. 1992 Nov 4;268(17):2420-5. doi:10.1001/jama.1992.03490170092032.
  2. Gajewski P, Jaeschke R, Brożek J, eds. Podstawy EBM czyli medycyny opartej na danych naukowych dla lekarzy i studentów [The fundamentals of evidence-based medicine for physicians and students; in Polish]. Medycyna Praktyczna; 2008.
  3. Guyatt G, Rennie D, Meade MO, Cook DJ, eds. Users’ Guides to the Medical Literature: A Manual for Evidence-Based Clinical Practice. 3rd ed. McGraw-Hill Education; 2015.
  4. The GRADE Working Group.