Evidence-Based Medicine Working Group, Anonymous. Evidence-based
medicine. A new approach to teaching the practice of
medicine. JAMA 1992 Nov
4;268(17):2420-5.
The former paradigm
was based on the following assumptions about the knowledge required to guide
clinical practice.
According to this
paradigm clinicians have a number of options for sorting out clinical problems
they face. They can reflect on their own clinical experience, reflect on the
underlying biology, go to a textbook, or ask a local expert. The
"Introduction" and "Discussion" sections of a paper could
be considered an appropriate way of gaining the relevant information from a
current journal.
It should be noted
that this paradigm puts a high value on traditional scientific authority and
adherence to standard approaches, and answers are frequently sought from direct
contact with local experts, or reference to the writings of international
experts [19].
The assumptions of
the new paradigm are as follows.
It follows that
clinicians should regularly consult the original literature (and read and be
able to critically appraise the "Methods" and "Results"
sections) in solving clinical problems and providing optimal patient care. It
also follows that clinicians must be ready to accept and live with uncertainty,
and to acknowledge that management decisions are often made in the face of
relative ignorance of their true impact.
The new paradigm
puts a much lower value on authority [20]. The underlying
belief is that physicians can gain the skills to make independent assessments
of evidence, and thus evaluate the credibility of opinions being offered by
experts. The decreased emphasis on authority does not imply a rejection of what
one can learn from colleagues and teachers whose years of experience have
provided them with insight into methods of history-taking, physical
examination, and diagnostic strategies which can never be gained from formal
scientific investigation. A final assumption of the new paradigm is that
physicians whose practice is based on an understanding of the underlying
evidence will provide superior patient care.
The role-modelling,
practice, and teaching of evidence-based medicine requires skills that are not
traditionally part of medical training. These include precisely defining a
patient problem, and what information is required to resolve the problem;
conducting an efficient search of the literature; selecting the best of the
relevant studies, and applying rules of evidence to determine their validity [3]; being able to present
to colleagues in a succinct fashion the content of the article, and its
strengths and weaknesses; extracting the clinical message, and applying it to
the patient problem. We will refer to this process as the "critical
appraisal exercise."
Evidence-based medicine also involves applying
traditional skills of medical training. A sound understanding of pathophysiology is necessary to interpret and apply the
results of clinical research. For instance, most patients to whom we would like
to generalize the results of randomized trials would, for one reason or
another, not have been enroled in the most relevant
study. The patient may be too old, be too sick, have other underlying illness,
or be uncooperative. Understanding the underlying pathophysiology
allows the clinician to better judge whether the results are applicable to the
patient at hand. Understanding of pathophysiology
also has a crucial role as a conceptual and memory aid.
A second traditional skill required of the
evidence-based physician is a sensitivity to patients'
emotional needs. Understanding patients' suffering [21], and how that
suffering can be ameliorated by the caring and compassionate physician, are
fundamental requirements for medical practice. These skills can be acquired
through careful observation of patients and of physician role-models. Here too,
though, the need for systematic study, and the limitations of the present
evidence, must be considered. The new paradigm would call for using the
techniques of behavioral science to determine what patients are really looking
for from their physicians [22],
and how physician and patient behavior affects the outcome of care [23]. Ultimately,
randomized trials of different strategies for interacting with patients (such
as the randomized trial conducted by
Since evidence-based medicine involves skills
of problem definition, searching, evaluating, and applying original medical
literature, it is incumbent on residency programs to teach these skills.
Understanding the barriers to educating physicians-in-training in
evidence-based medicine can lead to more effective teaching strategies.