Medical publications distributed freely to health professionals often promote drugs that are costly or have potential problems, says a new study warning that such practices could influence which drugs doctors prescribe.
Unlike medical publications that require paid subscriptions, free journals get most or all of their funding from pharmaceutical advertising.
A group of researchers keen to discover what effect industry ties have on the content of published medical journals conducted a detailed comparison of journals that are free, those that have some pharmaceutical advertising and subscription fees, and those that are subscription-only.
Their findings, published on Monday in the Canadian Medical Association Journal, show that free journals are much more likely than other publications to display ads for new drugs that are more expensive than older, generic versions as well as drugs that are linked to some concerns over effectiveness.
But the researchers also discovered that free journals frequently print editorial content that directly recommends the drugs that are advertised in the journal.
"It's pretty well drug company advertising," said Joel Lexchin, a professor in the School of Health Policy and Management at York University in Toronto and one of the study's authors. "These journals probably have a role in influencing prescribing behaviour."
Free medical publications tend to contain easy-to-digest articles and usually don't publish original, peer-reviewed research papers. They are ubiquitous in health-care settings across Canada and other countries, a worrying trend because it is difficult, if not impossible, for doctors and other professionals to detect industry bias without launching their own detailed investigation, the study says.
"That's what we hope to come out of this study, that physicians wake up and are a bit more aware of the bias they get," said Norbert Donner-Banzhoff, one of the study's authors and a professor of family medicine at the Philipps University of Marburg in Germany.
In the study, researchers examined 465 issues of 11 journals frequently read by general practitioners in Germany for references to a group of pre-selected drugs. The drugs were chosen because they were still protected by patent and thus more expensive than other medications used to treat similar conditions, or because there was concern over their effectiveness.
In the free journals, researchers found nearly 600 advertisements and more than 250 editorial articles recommending drugs in the pre-selected group.
But in subscription-only journals, which do not rely heavily on drug advertising money, researchers identified only 34 articles recommending drugs in the pre-selected group. They found no advertisements of those drugs in subscription-based journals and noted that those journals often recommended against the use of drugs in the pre-selected list.
Only one journal with a mix of drug advertising and subscription revenues was included in the study; Researchers identified 46 drug advertisements and seven articles endorsing the pre-selected group of drugs in the issues of that journal that were examined.
That is not to say subscription-only journals are beyond reproach. The Lancet, one of the world's more respected journals, published deeply flawed research in 1998 linking vaccines and autism, sparking a backlash against immunization that continues today. The journal officially retracted the article last year.
But concerns over free medical journals are pressing because they can have real consequences on how physicians prescribe drugs, according to Aaron Kesselheim of Brigham and Women's Hospital and Harvard Medical School in Boston.
"Covert promotion of pharmaceuticals is an important public-health issue because it can contribute to the unnecessary overuse of certain drugs or lead to their off-label use without sufficient evidence of efficacy," Dr. Kesselheim wrote in a commentary published alongside the study.