[Evidence based medicine. A new paradigm for medical practice].

Modern medical practice is an ever-changing process, and the doctor's need for information has been partially met by continuous medical education (CME) activities. It has been shown that CME activities have not prevented clinical knowledge, as well as medical practice, from deteriorating with time. When faced with the need to get the most recent and relevant information possible, the busy clinician has two major problems: most of the published medical literature is either irrelevant or not useful; and there is little time to read it. Evidence-based medicine constitutes a new paradigm for medical practice in the sense that it tries to transform clinical problems into well formulated clinical questions, selecting and critically appraising scientific evidence with predefined and rigorous rules. It combines the expertise of the individual clinician with the best external evidence from clinical research for rational, ethical and efficacious practice. Evidence-based medicine can be taught and practiced by physicians with different degrees of autonomy, with several subspecialties, working in the hospital or in outpatient clinics, alone or in groups.