http://www.buffalo.edu/news/13493
Buffalo, N.Y. -- A new University at Buffalo study of publications in the
world's top five general medical journals finds that when clinical trials do not
account for participants who dropped out, results are biased and may even lead
to incorrect conclusions.
Published recently in the British Medical Journal, the methodological study
open access at
http://www.bmj.com/content/344/bmj.e2809
consisted of a systematic analysis of 235 clinical trials published in the
world's top five general medical journals between 2005 and 2007 that claimed a
statistically significant effect.
"We found that in up to a third of trials, the results that were reported as
positive -- in other words, statistically significant -- would become negative
-- not statistically significant, if the investigators had appropriately taken
into consideration those participants who were lost to follow-up," says Elie A.
Akl, MD, MPH, PhD, lead author, and associate professor of medicine, family
medicine and social and preventive medicine at the University at Buffalo School
of Medicine and Biomedical Sciences and School of Public Health and Health
Professions. He also has an appointment at McMaster University.
"In other words, one of three claims of effectiveness of interventions made in
top general medical journals might be wrong," he says...