The Federal Trade Commission has ruled that doctors in Michican and dentists in Indiana violated federal antitrust laws by conspiring to thwart attempts by insurers to control health care costs.

In two unanimous decisions, the commission banned the Michigan State Medical Society from trying to control payment policies of health insurers and from negotiating fees for its members, and ordered the Indiana Federation of Dentists to permit members to turn over dental X-rays for examination by insurers.

The decisions Friday were the first FTC rulings in the health field since the American Medical Association lost a major legislative battle in the last session of Congress to strip the commission's jurisdiction over health professionals.

While these two FTC decisions attacked practices of doctors and dentists to regulate fees, there were indications the commissioners recognized organized medicine's political clout. In both cases, the commission softened its administrative law judge's original order--in Indiana by allowing the dental federation to continue operating as long as its stops "coercing dental insurers," and in Michigan by letting the medical society discuss Blue Cross-Blue Shield payment policies as long as no agreements were forged.

Nonetheless, taken together the FTC rulings send a strong signal that the commission is not withdrawing from the health field despite AMA promises to continue the legislative battle this year. The AMA, which threw almost $2.5 million in campaign contributions into the fight, insisted it gained a victory last year because nothing in the FTC money bill specifically gives the FTC power to regulate professionals.

"Dentistry is a business, and the business practices of dentists are subject to the same antitrust laws as are business practices of manufacturers, jobbers and retailers," wrote Commissioner Michael Pertschuk in the Indiana dental case.

There, the commission found that dentists had banded together to stop insurance companies from using X-rays to determine if patients had received the least expensive form of treatment. This, the commission said, led to a coordinated refusal to submit X-rays for claims review; reduced competition among dentists, and thwarted insurance company efforts to contain dental costs.

The FTC found that the Michigan State Medical Society had threatened boycotts to force Blue Cross-Blue Shield to follow fee schedules set by the doctors.