Studies about medications published in the most influential medical journals are frequently designed in a way that yields misleading or confusing results, new research suggests.

Investigators from the medical schools at UCLA and Harvard analyzed all the randomized medication trials published in the six highest-impact general medicine journals between June 1, 2008, and Sept. 30, 2010, to determine the prevalence of three types of outcome measures that make data interpretation difficult.

In addition, they reviewed each study’s abstract to determine the percentage that reported results using relative rather than absolute numbers, which can also be a misleading.

The findings are published online in the Journal of General Internal Medicine.

The six journals examined by the investigators- the New England Journal of Medicine, the Journal of the American Medical Association, The Lancet, the Annals of Internal Medicine, the British Medical Journal and the Archives of Internal Medicine – included studies that used the following types of outcome measures, which have received increasing criticism from scientific experts:

Surrogate outcomes (37 percent of studies), which refer to intermediate markers, such as a heart medication’s ability to lower blood pressure, but which may not be a good indicator of the medication’s impact on more important clinical outcomes, like heart […]