Reports of research on drugs tend to exaggerate the drugs' benefits, making them sound better than they really are, according to an article and editorial being published today in the Journal of the American Medical Association.
The exaggeration occurs for several reasons, the journal said: Positive results tend to be published more often than negative ones, researchers sometimes publish the same study more than once, and some poorly designed studies slip through the safety net of journal editors and expert reviewers who should screen them out.
The effect of such research harms patients, because doctors rely on it to make decisions about treatment, said Dr. Drummond Rennie, a deputy editor of the journal and author of the editorial. Decisions based on misinformation may result in patients' being given an inferior drug or a new, expensive one that looked good in a study but that is really no better than an older, cheaper medicine.
"Ultimately, the patient is shortchanged," Rennie said.
His editorial and the journal article describe studies on drugs used to treat people with rheumatoid arthritis, post-surgical vomiting, depression, schizophrenia and immune deficiency resulting from cancer. Much of the research, like drug research generally, was financed by pharmaceutical companies, which often stand to benefit from the false impressions.
But Rennie attributed the problem not only to drug companies, but also to researchers and the institutions that allow shoddy research, and to journal editors and scientific reviewers who do not discern or blow the whistle on flawed or deceptive studies.
"Peer review does its best, but it's only as good as the people doing it, and the honesty of the people doing it," Rennie said, referring to the system in which journals ask experts to review papers being considered for publication.
Rennie and the other authors, Dr. Helle Krogh Johansen and Dr. Peter C. Gotzsche, of the Nordic Cochrane Center in Copenhagen, Denmark, described several sources of distortion in medical research. One is "publication bias," meaning that studies showing positive results from drugs are published faster and more often than studies showing neutral or negative results, which may never be published.
Dr. Kay Dickersin, an associate professor of community health at Brown University who has extensively studied publication bias, said that many scientists had blamed journal editors for refusing to publish negative results, but that she and her colleagues had found that the scientists themselves held back the findings.