Drug Trials May Influence Doctors' Prescribing Patterns

But not to the detriment of patients, study finds

TUESDAY, June 20, 2006 (HealthDay News) -- Doctors who participated in a drug company-sponsored trial of asthma medications were more likely to prescribe that company's drugs.

But, participating in the trial had no impact on the physicians' adherence to international treatment guidelines for asthma, concluded a Danish study in the June 21 issue of the Journal of the American Medical Association.

"The study authors conclude -- and I think correctly -- that physician involvement is a powerful tool for influencing specific drug preferences," said Dr. Bruce M. Psaty, author of an accompanying editorial in the journal and professor of medicine and epidemiology at the University of Washington, Seattle.

According to Psaty's editorial, this pattern is part of a much broader picture. "There are many areas of influence where industry tries to influence prescribing practices," he said. "There is influence on trial reporting and results, and also the trial questions they agree to fund."

More and more studies and papers are addressing this bigger picture, including a recent report that found that clinical trials funded by drug companies and other for-profit entities were more likely to report positive findings for the drug in question than similar trials funded by nonprofit groups.

A study published earlier this year found that industry is paying for more and more medical research, with half of all studies now funded solely by the private sector. And while physicians are often involved in company-sponsored clinical trials, the effects of their participation have not been fully studied, according to background information in the new paper.

Using a company's drugs can raise physicians' comfort level. For example, Psaty said, companies used to pay physicians to participate in "seeding" trials, where they put patients on a drug and agreed to collect minimal data.

"No good information comes from it, but the physician learns how to spell the drug name and the appropriate dosing," Psaty explained. "He feels comfortable with it."

Although those trials are no longer allowed, the trials that are the subject of the new study are only "marginally different," he said.

These study authors compared 10 Danish medical practices that were involved in a trial of asthma medicine with 165 practices that were not participating in any such trial. In all, the study involved 5,439 patients being treated with asthma drugs in the trial-related practices and 59,574 patients in the control practices.

Use of inhaled steroids among asthma patients increased from 68.5 percent to 72.9 percent during the second year in the practices involved in the trial and from 69.1 percent to 73.3 percent in the other practices.

The trial had no impact on how doctors adhered to international treatment guidelines, but it did affect which specific drugs were favored.

The study was sponsored by drug manufacturer AstraZeneca, Denmark. The company contributed data for the trial, but was not involved in the study's design and interpretation of the data.

Use of the sponsor's drug increased from 74.8 percent to 81.5 percent in the practices participating in the trial but only from 73.6 percent to 76.6 percent in the control practices.

Alan Goldhammer, associate vice president for regulatory affairs at the Pharmaceutical Research and Manufacturers of America (PhRMA), said, "Our position is patients get the right medication for their disease and treatment guidelines for asthma are followed. That's good. There may have been a bias, but it's difficult to make a direct correlation."

Thousands of small trials involving different drugs are conducted by investigators who then can influence their students or colleagues, Psaty contended.

"Agreeing to work on such a trial may represent a commitment to a scientific endeavor and at the same time be part of a marketing issue," Psaty said. "The scientific rationale for launching these thousands of small trials is not clear. My own bias is that the health of the public would be better served by fewer small trials and more long-term studies that fully address the health benefits and health risks of drugs."

"I'm not against companies coming up with good products," he added. "I'm for it, and those products can then be used appropriately to enhance the health of the public."

More information

For more on clinical trials, visit the National Institutes of Health.

SOURCES: Bruce M. Psaty, M.D., Ph.D., professor of medicine and epidemiology, University of Washington, Seattle; Alan Goldhammer, associate vice president for regulatory affairs, Pharmaceutical Research and Manufacturers of America, Washington, D.C.; June 21, 2006, Journal of the American Medical Association
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