[Evidence-based medicine: basic principles].

Evidence-based medicine : basic principles. The clinical judgment of health professionals is improving over the time of experience, but they need to keep their medical knowledge up to date. Yet, practitionners are inundated by an exponentially increasing biomedical literature, whom quality is questioned. Evidence-based medicine (EBM) provides a useful framework by integrating the best available clinical evidence from systematic research with individual clinical expertise and the patient's values and situation for the sake of clinical decision making. The practice of EBM involves five steps. The first one starts from a real case and aims at formulating a simple clinical question structured in the « PICO » format: patient (P) profile, intervention (I), comparator (C) and outcome (O) of interest. The second step consists in locating the available evidence through a literature search focusing primarily on pre-evaluated articles or synthesis (Cochrane). The third step is a critical appraisal of the best available evidence for validity, importance and usefulness of the results for the current patient. The fourth step combines the evidence with the clinical judgment and patient's values and preferences. Once the exercise is completed for a specific patient, the fifth step consists in rating one's performance to keep updated. Clinical questions can be formulated in 4 main areas of case management: diagnosis, treatment, prognostic or etiology. This article presents an example in the area of treatment. The EBM approach is important for the development of practitionners' abilities to find, critically appraise and incorporate the best scientific evidence for the benefit of their patients.