Studies about medications published in the most influential journals are frequently designed in a way that yields misleading or confusing results, according to a recent study conducted by the medical schools of UCLA and Harvard.* The journals used for this study were NEJM, JAMA, The Lancet, Annals of Internal Medicine, the British Medical Journal and the Archives of Internal Medicine.
Investigators analyzed all the randomized medication trails published in these six highest-impact general medicine journals between June 1, 2008 and September 30, 2010 to determine the prevalence of three types of outcome measures that make data interpretation difficult. They also reviewed each study’s abstract to determine the percentage that reported results using relative rather than absolute numbers which can be misleading.
The investigators discovered that trials that used surrogate outcomes and disease-specific mortality were more likely to be exclusively funded – for instance by pharmaceutical companies.
While 45% if exclusively commercially funded trials used surrogate endpoints, only 29% of trials receiving non-commercial funding did. And while 39% of exclusively commercially funded trials used disease-specific mortality, only 16% of trials receiving non-commercial funding did.
The researchers suggest that commercial sponsors of research may promote the use of outcomes that are most likely to indicate favorable results for their products.
“For example, it may be easier to show that a commercial product has a beneficial effect on a surrogate marker like blood pressure than on a hard outcome like a heart attack,” said lead author Dr. Michael Hochman, a fellow in the Robert Wood John Foundation Clinical Scholars Program at the David Gaffen School of Medicine at UCLA’s division of general internal medicine and health services research, and at the US Department of Veterans Affairs’ Los Angeles Medical Center. “In fact, studies in our analysis using surrogate outcomes were more likely to report positive results than those using hard numbers like heart attacks,” he said.
The UCLA-Harvard study also shows that 44% of study abstracts in these journals reported results exclusively in relative rather than absolute numbers which can be misleading. “The way in which results are presented is critical,” said Dr. Danny McCormick, the study’s senior author and a physician at the Cambridge Health Alliance and Harvard Medical School. “It’s one thing to say a medication lowers your risk of heart attacks from two-in-a-million or one-in-a-million and something completely different to say a medication lowers your risk of heart attacks by 50 percent.”
“Knowing the effects of a medication on blood pressure does not always tell you what the effect will be on the things that are important, like heart attacks or strokes,” said Hochman. “Similarly, patients don’t care if a medication prevents deaths from heart disease if it leads to an equivalent increase in deaths from cancer.”
*Hochman M, McCormick D. Endpoint Selection and Relative (Versus Absolute) Risk Reporting in Published Medication Trials. Journal of General Internal Medicine August 2011; DOI:10.1007, 11606-1813-7.
Reprinted with permission from International Review of Chiropractic, Volume 66, No. 1, 2011 by Dr. Karl R.O.S. Johnson, DC and Johnson Chiropractic Neurology & Nutrition