Evidence-Based Medicine A New Approach to Teaching the Practice of Medicine Evidence-Based Medicine Working Group A NEW paradigm for medical practice dose of phenytoin intravenously and the year is between 43% and 51%, and at 3 is emerging. Evidence-based medicine drug is continued orally. A computed years the risk is between 51% and 60%. de-emphasizes intuition, unsystematic tomographic head scan is completely nor¬ After a seizure-free period of 18 months clinical experience, and pathophysiolog- mal, and an electroencephalogram shows his risk of recurrence would likely be ic rationale as sufficient grounds for clin- only nonspecific findings. The patient is less than 20%. She conveys this infor¬ ical decision making and stresses the very concerned about his risk of seizure mation to the patient, along with a rec¬ examination of evidence from clinical re- recurrence. How might the resident ommendation that he take his medica¬ search. Evidence-based medicine re- proceed? tion, see his family doctor regularly, and quires new skills of the physician, in- have a review of his need for medication cluding efficient literature searching and The Way of the Past ifhe remains seizure-free for 18 months. the application of formal rules of evi- Faced with this situation as a clinical The patient leaves with a clear idea of dence evaluating the clinical literature. clerk, the resident was told by her se¬ his likely prognosis. An important goal of our medical res- nior resident (who was supported in his idency program is to educate physicians view by the attending physician) that A PARADIGM SHIFT in the practice of evidence-based med- the risk of seizure recurrence is high Thomas Kuhn has described scientific icine. Strategies include a weekly, for- (though he could not put an exact num¬ paradigms as ways of looking at the mal academic half-day for residents, de- ber on it) and that was the information world that define both the problems that voted to learning the necessary skills; that should be conveyed to the patient. can legitimately be addressed and the recruitment into teaching roles of phy- She now follows this path, emphasizing range of admissible evidence that may sicians who practice evidence-based to the patient not to drive, to continue bear on their solution.4 When defects in medicine; sharing among faculty of ap- his medication, and to see his family an existing paradigm accumulate to the proaches to teaching evidence-based physician in follow-up. The patient leaves extent that the paradigm is no longer medicine; and providing faculty with in a state of vague trepidation about his tenable, the paradigm is challenged and feedback on their performance as role risk of subsequent seizure. replaced by a new way of looking at the models and teachers of evidence-based world. Medical practice is changing, and medicine. The influence of evidence- The Way of the Future the change, which involves using the based medicine on clinical practice and The resident asks herselfwhether she medical literature more effectively in medical education is increasing. knows the prognosis of a first seizure guiding medical practice, is profound and realizes she does not. She that it can be called CLINICAL SCENARIO proceeds enough appropriately to the library and, using the Grateful a paradigm shift. A junior medical resident working in Med program,1 conducts a computerized The foundations of the paradigm shift a teaching hospital admits a 43-year-old literature search. She enters the Med¬ lie in developments in clinical research previously well man who experienced a ical Subject Headings terms epilepsy, over the last 30 years. In 1960, the ran¬ witnessed grand mal seizure. He had prognosis, and recurrence, and the pro¬ domized clinical trial was an oddity. It is never had a seizure before and had not gram retrieves 25 relevant articles. Sur¬ now accepted that virtually no drug can had any recent head trauma. He drank veying the titles, one2 appears directly enter clinical practice without a demon¬ alcohol once or twice a week and had not relevant. She reviews the paper, finds stration of its efficacy in clinical trials. had alcohol on the day of the seizure. that it meets criteria she has previously Moreover, the same randomized trial Findings on physical examination are learned for a valid investigation ofprog¬ method increasingly is being applied to normal. The patient is given a loading nosis,3 and determines that the results surgical therapies6 and diagnostic tests.6 are applicable to her patient. The search Meta-analysis is gaining increasing ac¬ costs the resident $2.68, and the entire ceptance as a method of summarizing the A complete list of members of the Evidenced-Based process (including the trip to the library results of a number of randomized trials, Medicine Working Group appears at the end of this ar- and the time to make a photocopy of the and ultimately may have as profound an ticle. article) took half an hour. effect on treatment as have Reprint requests to McMaster University Health Sci- setting policy ences Centre, Room 3W10,1200 Main St W, Hamilton, The results ofthe relevant study show randomized trials themselves.7 While Ontario, Canada L8N 3Z5 (Gordon Guyatt, MD). that the patient risk of recurrence at 1 less dramatic, crucial methodological ad- Downloaded from www.jama.com at Vrije Universiteit on August 22, 2009 vanees have also been made in other ar¬ sense is sufficient to allow one to eval¬ uncertainty and to acknowledge that eas, such as the assessment of diagnostic uate new tests and treatments. management decisions are often made tests8·9 and prognosis.2 4. Content expertise and clinical ex¬ in the face of relative ignorance of their A new philosophy of medical practice perience are a sufficient base from which true impact. and teaching has followed these meth¬ to generate valid guidelines for clinical The new paradigm puts a much lower odological advances. This paradigm shift practice. value on authority.20 The underlying be¬ is manifested in a number of ways. A According to this paradigm clinicians lief is that physicians can gain the skills profusion of articles has been published have a number of options for sorting out to make independent assessments of ev¬ instructing clinicians on how to access,10 clinical problems they face. They can idence and thus evaluate the credibility evaluate,11 and interpret12 the medical reflect on their own clinical experience, of opinions being offered by experts. literature. Proposals to apply the prin¬ reflect on the underlying biology, go to The decreased emphasis on authority ciples of clinical epidemiology to day- a textbook, or ask a local expert. Read¬ does not imply a rejection of what one to-day clinical practice have been put ing the introduction and discussion sec¬ can learn from colleagues and teachers, forward.3 A number of major medical tions of a paper could be considered an whose years of experience have provid¬ journals have adopted a more informa¬ appropriate way of gaining the relevant ed them with insight into methods of tive structured abstract format, which information from a current journal. history taking, physical examination, and incorporates issues of methods and de¬ This paradigm puts a high value on diagnostic strategies. This knowledge sign into the portion of an article the traditional scientific authority and ad¬ can never be gained from formal scien¬ reader sees first.13 The American Col¬ herence to standard approaches, and an¬ tific investigation. A final assumption of lege of Physicians has launched a jour¬ swers are frequently sought from direct the new paradigm is that physicians nal, ACP Journal Club, that summa¬ contact with local experts or reference whose practice is based on an under¬ rizes new publications of high relevance to the writings ofinternational experts.19 standing ofthe underlying evidence will and methodological rigor.14 Textbooks care. The New provide superior patient that provide a rigorous review of avail¬ Paradigm REQUIREMENTS FOR THE able evidence, including a methods sec¬ The assumptions ofthe new paradigm PRACTICE OF EVIDENCE-BASED tion describing both the methodological are as follows: criteria used to systematically evaluate 1. Clinical experience and the devel¬ MEDICINE the validity of the clinical evidence and opment of clinical instincts (particularly The role modeling, practice, and teach¬ the quantitative techniques used for with respect to diagnosis) are a crucial ing of evidence-based medicine requires summarizing the evidence, have begun and necessary part of becoming a com¬ skills that are not traditionally part of to appear.1516 Practice guidelines based petent physician. Many aspects of clin¬ medical training. These include precise¬ on rigorous methodological review ofthe ical practice cannot, or will not, ever be ly defining a patient problem, and what available evidence are increasingly com¬ adequately tested. Clinical experience information is required to resolve the mon.17 A final manifestation is the grow¬ and its lessons are particularly impor¬ problem; conducting an efficient search ing demand for courses and seminars tant in these situations. At the same of the literature; selecting the best of that instruct physicians on how to make time, systematic attempts to record ob¬ the relevant studies and applying rules more effective use of the medical liter¬ servations in a reproducible and unbi¬ of evidence to determine their validity3; ature in their day-to-day patient care.3 ased fashion markedly increase the con¬ being able to present to colleagues in a We call the new paradigm "evidence- fidence one can have in knowledge about succinct fashion the content of the ar¬ based medicine."18 In this article, we de¬ patient prognosis, the value of diagnos¬ ticle and its strengths and weaknesses; scribe how this approach differs from tic tests, and the efficacy of treatment.