[What is evidence-based medicine?]

Evidence-based medicine is based on the best results from clinical and epidemiological research, which is combined with clinical experience and patient preferences. Questions of prognosis and harm are often best elucidated in large cohort studies. For other clinical questions the best evidence is usually found by systematic review of randomised trials, if possible in the form of meta-analyses. To make a diagnosis is, for example, not an aim in itself but a way to arrive at a prognosis and to suggest a treatment, provided this leads to a better prognosis. The most relevant, albeit rarely seen, test of a diagnostic method is a randomised trial. Evidence-based medicine will provide the best basis for evaluations of which interventions should be abandoned and which are effective and economically feasible. The use of evidence-based clinical guidelines will lead to more cost-effective treatments. It should be a national strategy that health care should be evidence-based.