This article comes from Clinical Evidence, a new resource for clinicians, p
roduced jointly by the BMJ Publishing Group and the American College of Phy
sicians-American Society of Internal Medicine. Clinical Evidence is an exte
nsively peer-reviewed publication that summarizes the best available eviden
ce on the effects of common clinical interventions gleaned from thorough se
arches and appraisal of the world literature. The first issue is available
in book form in the United Kingdom, with a United States version planned fo
r publication in October. The second issue, updated and expanded to cover m
ore topics and questions, will be published 6 months later. Please see the
advertisement For more information or visit our web site at www.evidence.or
g.