Skewed Results? Failure to Account for Clinical Trial Drop-Outs Can Lead to Erroneous Findings in Top Medical Journals - UB NewsCenter

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Skewed Results? Failure to Account for Clinical Trial Drop-Outs

Can Lead to Erroneous Findings in Top Medical Journals

Up to a third of clinical trials studied that found an

intervention effective might, in fact, be wrong

Release Date: June 13, 2012

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...