Publication Bias Seen in Published Drug Trials
Only 43 percent of trials supporting new drugs get into literature
MONDAY, Sept. 29 (HealthDay News) -- Trials supporting the applications for a variety of new drugs appear to be affected by publication bias, which may lead to an inappropriately favorable representation of the drug in the medical literature, according to research published in the September issue of PLoS Medicine.
Kirby Lee, of the Department of Clinical Pharmacy at the University of California San Francisco, and colleagues assessed data concerning 909 trials supporting 90 drugs that the U.S. Food and Drug Administration approved between 1998 and 2000. The authors were chiefly interested in the time from FDA approval to publication of a full report, and whether a report was published by two or five years after the drug's approval.
Of the 909 trials, only 43 percent were published in the medical literature, the researchers report, and 76 percent of trials deemed "pivotal" were published. Factors associated with a higher likelihood of publication include statistically significant results (odds ratio, 3.03), larger sample sizes (OR, 1.33 per twofold increase in size) and pivotal status (OR, 5.31), the report indicates.
"The FDA Amendments Act of 2007 mandates basic public results reporting for all trials supporting FDA-approved drugs and devices. Our study shows that this legislation was necessary because current reporting is marked by pervasive publication bias of positive over negative trials. Moreover, because published trial reports are often incomplete and have been shown to selectively report favorable outcome results, the published evidence supporting FDA-approved drugs may be even more skewed than our results suggest," the authors write.