Conflicts of interest overlooked in drug trial reviews: Study

By Dr. Ananya Mandal, MDMar 8 2011

A new study shows that researchers who review large sets of drug trials for medical journals – also known as meta analysis - often ignore financial conflicts that might affect the evidence and thereby conclusions.

Experts believe that the problem is not merely academic because the reviews and meta analysis are considered just about the strongest evidence or gold standard that medical science can depend on. Brett D. Thombs, of McGill University and the Jewish General Hospital in Montreal, whose findings are published in the Journal of the American Medical Association (JAMA) said, “It influences how physicians make decisions and how guideline panels come up with their guidelines.”

The team looked at multiple reviews and found that of 29 reviews culled from top journals like JAMA and The Lancet, only two reported who had funded the original trials included in the review. And none of the reviews mentioned whether the authors reporting on those trials had been paid by drugmakers or pharmaceutical companies. Such financial ties have been linked to research exaggerating the benefits of new drugs and downplaying the risks, said Thombs.

He explained that a 2008 report said only half the trials on antidepressants sent to the U.S. Food and Drug Administration, which approves new drugs, got a positive review by the agency. However from the medical literature it appeared that more than 90 percent of the trials favored the drugs, because the majority of those that were unfavorable simply never got published.

Most journals now require authors to declare who funded their study and whether they have any financial conflicts of interest, such as paid consultancies for drugmakers. Thombs’ team found that more than two-thirds of the original drug trials that ended up being included in the 29 reviews were funded by pharmaceutical companies. Only 318 of the 509 trials reviewed gave the conflict-of-interest information in the first place. But most of the time, those financial disclosures got lost or were overlooked in the reviews. In addition, about one-fourth of the trials had author disclosures and, of these, almost 70 percent had at least one author with ties to the drug industry.

“Meta-analyses and other kinds of systematic reviews are often [used] to make decisions and judgments both by individual practitioners and by guidelines developers and pharmaceutical and therapeutic committees,” said Dr. Susan Dorr Goold, a professor of internal medicine and health management and policy at the University of Michigan in Ann Arbor.

Michelle Roseman, a graduate student at McGill who also worked on the new findings said, “What we noticed is there is a gap between these two levels.” When this study team contacted the reviewers, the majority admitted they had not even looked at the issue. Dr. Cynthia Mulrow, secretary of the International Committee of Medical Journal Editors, which has published guidelines for how to disclose conflicts of interest in medical journals calls this a “blind spot”. She said, “I do agree that reviewers who summarize evidence should be thinking about conflicts of interest and assessing that as something that could have potentially biased the findings.” She added that her colleagues would take the new findings into account in future updates.

Goold noted, “I don't think that we’re going to give up industry-funded clinical research, [but] it might be a good idea to have additional disinterested funding support to sort of check things and verify validity. We know there's a profit motive. There’s supposed to be a profit motive. I don’t think drug or device companies are evil.” But, she added, “as recipients of knowledge, doctors or guideline writers need to be looking a little bit differently at research that’s got that sort of funding relationship, [and] we need more data on what kinds of relationships have influence.”