Evidence-based medicine is a medical movement based upon the application of the scientific method to medical practice, including long-established existing medical traditions not yet subjected to adequate scientific scrutiny. According to the Centre for Evidence-Based Medicine (http://www.cebm.net/), "Evidence-based medicine is the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients."
Using techniques from science, engineering and statistics, such as meta-analysis of the existing literature, risk-benefit analysis and randomized controlled trials, it aims for the ideal that all doctors should make "conscientious, explicit, and judicious use of current best evidence" in making decisions about the care of individual patients.
Evidence-based medicine categorizes different types of clinical evidence and ranks them according to usefulness for guiding a treatment decision for an individual patient. For example, the strongest evidence is provided by randomized controlled prospective trials involving similar patients with similar conditions. In contrast, testimonials, hearsay and mystical arguments have little value as proof because the placebo effect, random events and observer bias distort perceptions.
Practising evidence-based medicine implies not only clinical expertise, but expertise in retrieving, interpreting, and applying the results of scientific studies, and in communicating the risks and benefit of different courses of action to patients.
For all its problems, evidence-based medicine has very successfully demoted the ex cathedra statement of the "medical expert" to the least valid form of evidence and all "experts" are now expected to be able to reference their pronouncements to the relevant literature.
Professor Archie Cochrane was a British medical researcher whose book Effectiveness and Efficiency: Random Reflections on Health Services (1972) and subsequent advocacy caused increasing acceptance of the evidence-based medicine concept. Cochrane's work was honoured through the naming of centres of evidence-based medical research — Cochrane Centres — and an international organisation, the Cochrane Collaboration.
Criticism of evidence-based medicine
Critics of evidence-based medicine state that doctors were doing these things already, that good evidence is often deficient in many areas, that lack of evidence and lack of benefit are not the same, and that the more data are pooled and aggregated the more difficult it is to compare the patients in the studies with the patient in front of the doctor. In The limits of evidence-based medicine (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11728302&dopt=Abstract), Tonelli argues that "the knowledge gained from clinical research does not directly answer the primary clinical question of what is best for the patient at hand." Evidence-based medicine seems to them to discount the value of the case study.
The primary problem is that evidence-based medicine is most effective when testing the effectiveness of drugs and may not be appropriate for other forms of treatment, particularly those requiring the active participation of the patient.
In America, evidence-based guidelines are used as the basis for denying insurance coverage for treatments which are generally held by physicians to be effective, but for which randomized, controlled trials have not yet been held.
- Centre for Evidence-Based Medicine (http://www.cebm.net/index.asp)
- Cochrane Collaboration: systematic reviews of the effects of health care interventions (http://www.cochrane.org/)
- Bandolier Journal: evidence-based thinking about health care (http://www.jr2.ox.ac.uk/bandolier/)
- 'Netting the Evidence' resource directory (http://www.shef.ac.uk/~scharr/ir/netting/)
- British Medical Journal editorial on evidence-based medicine (http://bmj.com/cgi/content/full/312/7023/71)
- British Medical Journal article on Evidence based medicine: Socratic dissent (http://www.bmj.com/cgi/content/full/310/6987/1126)