Expansion of Medicare and Medicaid may increase premiums for commercial group health plans in 2011, according to Milliman.

Group health insurance specialists at Milliman, Seattle, are making that prediction based on preliminary results from a 2010 group health insurance premium survey.

Milliman tries to promote “apples to apples” comparisons by asking health insurers to describe the premiums they would charge for a group with a given set of benefits and enrollee characteristics.

Preliminary results suggest that January 2011 renewal increases will be 9% for health maintenance organization plans and 11% for preferred provider organization plans, Milliman says.

Doug Proebsting, a consulting actuary at Milliman, says worries about the new federal health insurance laws may be one factor.

Efforts to expand Medicaid and Medicare may also be contributing to rising commercial plan costs, because government programs typically pay providers less than commercial plans pay, and providers may be charging privately insured patients more to make up for low government plan reimbursement rates, Proebsting says.

Milliman expects to release final group health premium survey results in October.

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