The American Medical Association, before winding up its 130th House of Delegates meeting in Chicago, voted against a leading health care bill that would cut medical costs by increasing competition while reducing regulation.

Although the bill is generally in line with administration thinking, it is not the official administration position because it is now being developed by the Department of Health and Human Services. But it was sponsored by Rep. Richard A. Gephardt (D-Mo.) with then-representative David A. Stockman (R-Mich.), who has since become director of the Office of Management and Budget.

An AMA spokesman said yesterday that the AMA isn't necessarily opposed to all pro-competition bills, although all have one major potential problem: possible restrictions on a patient's right to choose his doctor. But he said the Gephardt-Stockman measure introduced early this year was unacceptable.

Critics say a basic problem with the health care system in this country is that no one has a vested interest in restraining costs. This is mainly because so many bills tend to be paid through public program or under group insurance policies. Neither patient nor doctor has an incentive to hold back.

The pro-competition school wants to combat this by creating an array of insurance programs, some elaborate and costly and some not, then having patients choose. Companies would presumably compete to offer the best deals, partly by making arrangements with hospitals and doctors to provide services at fixed fees.

Insurors, hospitals and patients all would have incentives to hold costs down, the theory goes, and this could be done without more federal regulation, which many see as the only real alternative.

In the report adopted at the House of Delegates meeting Thursday, the AMA said the Gephardt bill, far from reducing federal regulation, could lead to greater federal control over the medicine, partly by authorizing the feds to move in to regulate insurance, which has been the province of the states, and which as an immense impact on the way doctors practice.

"Any time the federal government makes rules" and takes power away from the local governments, "we have a problem," one official said.

The report said the bill also permits the federal government to preempt a variety of state laws involving such matters as the corporate practice of medicine; staff appointment or admitting privileges in a hospital; regulation of health insurance premiums and other health insurance matters; the type of medical services that could be delivered by specified categories of health professionals; regulation, marketing, advertising and adminstration of health care plans and service.

All this federal regulation, the report said, would eventually "lead to, if not constitute, a federalization of the nation's health care system.

An added fear, one offical said, is that the patient's freedom to choose his doctor and hospital, and ultimately the medical procedures that can be used, could be restricted by the so-called pro-competition approach.

A key factor in that approach is that an insurance company must be able to hold down costs by getting selected hospitals and/or doctors to contract to perform services at a fixed fee.

A patient enrolling in an insurance plan thus might be required to use the services only of a panel of doctors and hospitals selected by the company, the AMA spokesman said.