As a result, nearly 30,000 patients covered by Aetna must accept doctors who remain under contract to the company.

They say that if Medicare payments are reduced, many hospitals will increase charges to patients covered by private health insurance.

And 90 percent of the city's 2,000 doctors were available to patients covered by both companies.

Some have effectively fired insurers that refused to pay up, refusing to accept patients covered by those plans.

Presbyterian officials today emphasized the Health Department's finding that there had been no difference in the quality of care provided to patients covered by Medicaid.

But poor patients covered by Medicaid may suffer after the switch.

But doctors said that if the cuts took effect, many physicians would be less willing to take elderly and disabled patients covered by Medicare.

Having lost this ability, a few physicians now refuse to see patients covered by Medicare.

Even patients covered by Medicare, the Government insurance program intended to protect the elderly from unforeseen health care costs, are feeling the squeeze.

To fill beds, many are actively courting poor patients covered by Medicaid.