Medical journals' impact on practice studied

Medical editors are looking for better ways to determine the far-reaching effects their journals have on physicians and other readers of scientific studies.

This discussion, reflected in several presentations at last month's International Congress on Peer Review and Biomedical Publication, stems from questions about whether "impact factor" is the best measure of a journal's scientific influence and ability to disseminate new technology. The impact factor is a computation that compares the number of times articles from a journal are cited with the number of articles that journal published overall.

"How else can we evaluate the impact of research?" asked Dr. Fiona Godlee, editor of the British Medical Journal and an organizer of the conference, which gathers leading medical editors every four years. "Is it possible to measure the impact on the clinician and health care itself?"

One study presented by editors of the Medical Journal of Australia analyzed the impact factors of seven general medical journals. It concluded that in the past decade, some editors increased this figure by recruiting important papers. Some, however, did so by reducing the total number of articles published.

"All considered the impact factor is a mixed blessing -- attractive to researchers but not the best measure of clinical impact," wrote the authors.

Researchers also attempted to quantify the effect of industry funding on clinical trials. Researchers found that its influence on study quality was either benign or negative. Industry backing, however, was linked to an increased likelihood of positive results. One paper by researchers at Harvard Medical School found that pharmaceutically funded studies of bipolar disorder tend to have lower drop-out rates and were more likely to support increased use of the drug manufactured by the company funding the study.

Several studies also found that meta-analyses with financial ties to a drug company were more likely to favor the medication in question.

"Systematic reviews of drugs should not be sponsored by industry," wrote the authors of one study from the Nordic Cochrane Centre in Copenhagen. "And if they are, they should not be trusted."