A consortium of 12 city hospitals and the D.C. Department of Human Services released preliminary recommendations yesterday in what was described as a cooperative effort to restrain the increasing cost of the Medicaid program.

Mayor Marion Barry said he was giving "top priority" to holding down the escalating cost of the federal-local program, which provides medical care for the poor.

In the District of Columbia, Medicaid provides care for 125,000 people and is the city government's single most costly program, according to Barry. The city's Medicaid program will cost $175 million in 1982 and an estimated $210 million next year. The average per capita cost rose 106 percent between 1975 and 1981, according to the preliminary report released yesterday.

Joseph A. Califano Jr., the former secretary of Health, Education and Welfare whose law firm is managing the study for the consortium, singled out two possible recommendations that will be the focus of the study's second phase.

One possibility for lowering hospital costs -- now roughly 50 percent of the Medicaid outlay -- is to negotiate a lump-sum payment with individual hospitals, or all of them as a unit, at the beginning of the year, giving the hospitals a fixed budget within which to care for Medicaid patients.

A second possible recommendation would be to pay physicians willing to accept Medicaid patients on a per-patient basis, rather than paying them according to the services performed as they are now reimbursed under the present system.

"What's at stake here," Califano said, "is whether or not the District of Columbia will be able to continue to provide quality health care for all of its citizens regardless of their ability to pay for it."

According to Barry and Califano, the city's health-care system for the poor is being squeezed by the increasing amounts the city is paying for Medicaid on the one side, and on the other by the increasing amounts of health care the hospitals are giving free to poor persons who are not eligible for Medicaid. Barry estimated that hospitals this year are providing more than $100 million in free care.

The study is being financed by grants of $25,000 each from the Robert Wood Johnson and Eugene and Agnes Meyer foundations, and $5,000 contributions from the city and each of the 12 participating hospitals: Capitol Hill, Children's, Columbia, D.C. General, George Washington, Georgetown, Greater Southeast, Hadley, the Hospital for Sick Children, Howard, Providence and Washington Hospital Center.

Sibley Memorial and the Psychiatric Institute declined to participate. Califano said he was donating the time he spends on the study.

The second phase of the study, with recommendations for decisions by the hospital and the city is due in January.