Evidence-based medicine: application in Alzheimer's disease research

The two fundamental principles of evidence-based medicine indicate that a hierarchy of evidence exists and that evidence alone is never sufficient to make clinical decisions. Incorporation of factors other than evidence such as patients' values and preferences, clinical context, and resource allocation are essential factors for decision making. The knowledge of these principles orients the use of clinical care research by evidence users such as patients, clinicians, and policy makers; and also helps researchers create research protocols and agendas that produce evidence that fulfills the needs of these users. Examples of research in Alzheimer's disease are presented to illustrate how evidence is produced, appraised and utilized.