This article is an editorial from
British Medical Journal 1996 (Jan 13); 312 (7023): 71–72 ~ FULL TEXT
David L Sackett, William MC Rosenberg, JA Muir Gray, R Brian Haynes, W Scott Richardson
Evidence-Based Medicine, whose philosophical origins extend back to mid-19th
century Paris and earlier, remains a hot topic for clinicians, public health
practitioners, purchasers, planners, and the public. There are now frequent workshops in how to practice and teach
it (one sponsored by this journal will be held in London on April 24th); undergraduate
 and post-graduate training programmes 
are incorporating it  (or pondering how to do so);
British centres for evidence-based practice have been established or planned
in adult medicine, child health, surgery, pathology, pharmacotherapy, nursing,
general practice, and dentistry; the Cochrane Collaboration and the York Centre
for Review and Dissemination in York are providing systematic reviews of the
effects of health care; new evidence-based practice journals are being launched;
and it has become a common topic in the lay media. But enthusiasm has been mixed
with some negative reaction [4-6]. Criticism has ranged
from evidence-based medicine being old-hat to it being a dangerous innovation,
perpetrated by the arrogant to serve cost-cutters and suppress clinical freedom.
As evidence-based medicine continues to evolve and adapt, now is a useful time
to refine the discussion of what it is and what it is not.
Evidence-based medicine is the conscientious, explicit
and judicious use of current best evidence in making decisions about the care
of individual patients. The practice of evidence-based medicine means integrating
individual clinical expertise with the best available external clinical evidence
from systematic research. By individual clinical expertise we mean the proficiency
and judgement that individual clinicians acquire through clinical experience
and clinical practice. Increased expertise is reflected in many ways, but especially
in more effective and efficient diagnosis and in the more thoughtful identification
and compassionate use of individual patients' predicaments, rights, and preferences
in making clinical decisi ons about their care. By best available external clinical
evidence we mean clinically relevant research, often from the basic sciences
of medicine, but especially from patient centred clinical research into the
accuracy and precision of diagnostic tests (including the clinical examination),
the power of prognostic markers, and the efficacy and safety of therapeutic,
rehabilitative, and preventive regimens. External clinical evidence both invalidates
previously accepted diagnostic tests and treatments and replaces them with new
ones that are more powerful, more accurate, more efficacious, and safer.
Good doctors use both individual clinical expertise and the best available external evidence, and neither alone is enough. Without clinical expertise, practice risks becoming tyrannised by evidence, for even excellent external evidence may be inapplicabl
e to or inappropriate for an individual patient. Without current best evidence, practice risks becoming rapidly out of date, to the detriment of patients.
This description of what evidence-based medicine is helps clarify what evidence-based medicine is not. Evidence-based medicine is neither old-hat nor impossible to practice. The argument that everyone already is doing it falls before evidence of striking variations in both the integration of patient values into our clinical behaviour  and in the rates with which clinicians provide interventions to their patients . The difficulties that clinicians face in keeping abreast of all the medical advances reported in primary journals are obvious from a comparison of the time required for reading (for general medicine, enough to examine 19 articles per day, 365 days pe
r year ) with the time available (well under an hour per week by British medical consultants, even on self-reports ).
The argument that evidence-based medicine can be conducted only from ivory towers and armchairs is refuted by audits in the front lines of clinical care where at least some inpatient clinical teams in general medicine , psych
iatry (JR Geddes, et al, Royal College of Psychiatrists winter meeting, January 1996), and surgery (P McCulloch, personal communication) have provided evidence-based care to the vast majority of their patients. Such studies show that busy clinici
ans who devote their scarce reading time to selective, efficient, patient-driven searching, appraisal and incorporation of
Evidence-based medicine is not "cook-book" medicine.
it requires a bottom-up approach that integrates the best external evidence
with individual clinical expertise and patient-choice, it cannot result in slavish,
cook-book appr oaches to individual patient care. External clinical evidence
can inform, but can never replace, individual clinical expertise, and it is
this expertise that decides whether the external evidence applies to the individual
patient at all and, if so, how it should be integrated into a clinical decision.
Similarly, any external guideline must be integrated with individual clinical
expertise in deciding whether and how it matches the patient's clinical state,
predicament, and preferences, and thus whether i t should be applied. Clinicians
who fear top-down cook-books will find the advocates of evidence-based medicine
joining them at the barricades.
Evidence-based medicine is not cost-cutting medicine. Some fear that
evidence-based medicine will be hijacked by purchasers and managers to cut the
costs of health care. This would not only be a misuse of evidence-based medicine
but suggests a fundamental misunderstanding of its financial consequences. Doctors
practising evidence-based medicine will identify and apply the most efficacious
interventions to maximise the quality and quantity of life for individual patients;
this may raise rather than lower the cost of their care.
Evidence-based medicine is not restricted to randomised trials and meta-analyses.
It involves tracking down the best external evidence with which to answer our
clinical questions. To find out about the accuracy of a diagnostic test, we
need to find proper cross-sectional studies of patients clinically suspected
of harbouring the relevant disorder, not a randomised trial. For a question
about prognosis, we need proper follow-up studies of patients assembled at a
uniform, early point in the clinical course of their disease. And sometimes
the evidence we need will come from the basic sciences such as genetics or immunology.
It is when asking questions about therapy that we should try to avoid the non-experimental
approaches, since these routinely lead to false-positive conclusions about efficacy.
Because the randomised trial, and especially the systematic review of several
randomised trials, is so much more likely to inform us and so much less likely
to mislead us, it has become the gold standard for judging whether
a treatment does more good than harm. However, some questions about therapy
do not require randomised trials (successful interventions for otherwise fatal
conditions) or cannot wait for the trials to be conducted. And if no randomised
trial has been carried out for our patients predicament, we follow the
trail to the next best external evidence and work from there.
Despite its ancient origins, evidence-based medicine remains a relatively
young discipline whose positive impacts are just beginning to be validated [12,
13], and it will continue to evolve. This evolution will be enhanced as
seve ral undergraduate, post-graduate, and continuing medical education programmes
adopt and adapt it to their learners needs. These programmes, and their
evaluation, will provide further information and understanding about what evidence-based
medicine is, and what it is not.
- David L. Sackett, Professor, NHS Research and Development Centre for Evidence-Based Medicine, Oxford.
William M. C. Rosenberg, Clinical Tutor in Medicine, Nuffield Department of Clinical Medicine, Oxford.
J. A. Muir Gray, Director of Research and Development, Anglia and Oxford Regional Health Auhtority, Milton Keynes
R. Brian Haynes, Professor of Medicine and Clinical Epidemiology, McMaster University Hamilton, Canada
W. Scott Richardson, Rochester, USA
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