A "new approach to teaching the practice of Medicine" described as a "paradigm shift," and called "evidence-based medicine" (EBM), was first discussed in 1992. 1 The paradigm was meant to replace an "authoritarian (opinion-based)" attitude in health-care with an "authoritative (evidence-based)" one. 1,2 This two part narrative review addresses some issues at the core of EBM. These include hierarchical levels, the randomized controlled trial (RCT), systematic (including Cochrane) reviews (SRs) and statistical methods to assess evidence. The objective is not only to inform but also to facilitate continuing dialogue on a paradigm that is now embedded in the teaching, practice, research, writings and management of health-care, 2-5 Neurosciences included. 6-8
METHODSThe principles out-lined in Straus et al, 2 were used to seek references pertinent to EBM, first through PubMed. The initial search term "Evidence-based Medicine" yielded 79,600 results. Limits were then placed: human; guidelines; reviews; systematic reviews; meta-analyses, and editorial confined to the English language. Additional searches were made using Medical Subject Headings (MeSH), "randomized controlled trials," "confidence intervals," "number needed to treat," "CONSORT," "levels of
ABSTRACT:The evidence-based medicine (EBM) paradigm, introduced in 1992, has had a major and positive impact on all aspects of health care. However, widespread use has also uncovered some limitations; these are discussed from the perspectives of two clinicians in this, the first of a two part narrative review. For example, there are credible reservations about the validity of hierarchical levels of evidence, a core element of the EBM paradigm. In addition, potential and actual methodological and statistical deficiencies have been identified, not only in many published randomized controlled trials but also in systematic reviews, both rated highly for evidence in EBM classifications. Ethical violations compromise reliability of some data. Clinicians need to be conscious of potential limitations in some of the cornerstones of the EBM paradigm, and to deficiencies in the literature. RÉSUMÉ: Paradigme de la médecine fondée sur des preuves : où en sommes-nous 20 ans plus tard? Première partie. Le paradigme de la médecine fondée sur des données probantes (MFDP) introduit en 1992 a eu un impact positif majeur sur tous les aspects des soins de santé. Cependant, son utilisation répandue a également mis au jour certaines limites. Nous discutons de ces limites du point de vue de deux cliniciens dans la première partie de cet examen narratif. Il existe, par exemple, des réserves crédibles concernant la validité des niveaux hiérarchiques de preuves, un élément clé du paradigme de la MFDP. De plus, des lacunes potentielles et réelles dans la méthodologie et l'analyse statistique ont été identifiées, non seulement dans plusieurs essais cliniques randomisés qui ont été publiés, mais également dans les revues systématiques, deux sources de données très prisées pour établir les classific...