Drug company promotions may influence doctors, study says.

Physicians who accept money from pharmaceutical companies to attend symposia or conduct research are more likely than other doctors to recommend drugs made by those companies, a new study has found.

Researchers at the Cleveland Veterans Affairs Medical Center surveyed physicians about their interactions with drug companies. They compared the responses of 40 doctors who had requested that a drug be added to the hospital formulary--a list of drugs available at the hospital--with the responses of 80 who had not made these requests.

The results showed "a strong and specific association" between physicians, requests for a particular drug and their interactions with the drug's manufacturer, wrote Mary-Margaret Chren and C. Seth Landefeld, the doctors who conducted the study. They found that "physicians who interacted with drug companies were from 9 to 21 times more likely than other physicians to have requested a drug made by the company with whom they had interacted." (Mary-Margaret Chren & C. Seth Landefeld, Physicians, Behavior and Their Interactions with Drug Companies, 271 JAMA 684 (1994).)

The survey asked physicians about four types of interactions with drug companies: meeting with company representatives, accepting money to attend educational symposia, accepting money to speak at symposia, and accepting money to conduct research. Generally, doctors who did not request formulary additions met with company representatives as often as doctors who made requests. However, doctors who made requests were much more likely to have accepted money.

Chren and Landefeld also found that physicians who made requests often asked for drugs with little or no therapeutic advantage over drugs already included in the formulary.

In an interview, Chren stressed that the study does not prove influence by drug makers. But, she added, "I think the most likely explanation is that doctors are influenced by their interactions with drug companies."

She said that interactions between physicians and pharmaceutical companies present a potential conflict of interest. "I think the results indicate that we in the medical profession should reexamine our relationships with drug companies, asking specifically whether they serve patients, needs first and foremost," Chren said.