A coalition of health care provider groups, social workers and advocates for the poor asked the federal government on Monday to reverse the state's decision to let insurers negotiate lower reimbursement for doctors and hospitals in the HUSKY health insurance program.

In a letter to federal administrators in Boston, the group protests the "unilateral" decision by Connecticut's Department of Social Services earlier this year to change one of the terms of the waiver, under which it operates the state's Medicaid managed care program, known as HUSKY A.

The department changed the portion of the 2009 waiver agreement that said that the insurers that offer HUSKY coverage - Aetna, AmeriChoice and the nonprofit Connecticut Health Network - must pay participating doctors and other providers of care at rates at least equal to those paid under traditional fee-for-service Medicaid.

The state dropped that requirement as of July 1 for all care providers, a move that the advocates said could imperil the quality of the HUSKY program, since doctors could be less likely to take HUSKY patients if their reimbursements patients are negotiated downward by insurers.

The change of policy is a violation of the terms of the waiver - the agreement between federal regulators and the state on how it will administer programs funded through Medicaid - and the change "threatens substantial harm to the approximately 400,000 enrollees in the HUSKY A health insurance program for low-income Connecticut families and children."

The letter was sent by Sheldon V. Toubman, a staff attorney at the New Haven Legal Assistance Association, Inc., to Richard McGreal, an assistant regional administrator for the Centers for Medicare and Medicaid Services in Boston.

Toubman's letter was sent on behalf of staffers from other interested groups, including the Connecticut Hospital Association, Christian Community Action, CT Parent Power, the National Association of Social Workers, the Connecticut State Medical Society, Advocacy for Patients with Chronic Illness, Greater Hartford Legal Aid and the state chapter of the American Academy of Pediatrics.

A spokesman for the Department of Social Services said the agency "is in a difficult position because we need to achieve critical savings in the state budget, and we're in contract renegotiations with HUSKY managed care plans toward that end."

"At the same time, we will continue to work with the legislature's Medicaid oversight council, medical providers, federal officials and others to address any concerns about HUSKY members' access to care," spokesman David Dearborn said.

The department objected to Toubman's use of a quote from Dr. Robert Zavoski - now the DSS medical director - who said in 2006 that providers in HUSKY are "paid so poorly that very, very few subspecialists are willing to do the care."

In a statement relayed by Dearborn, Zavoski said, "That quote came in support of a rate increase, which was enacted and implemented, therefore the citation is misleading."

t.mann@theday.com