Rates for the Medicare Part D prescription drug plans with the highest market share are set to increase about 10% in 2011.

When Medicare program managers announced the 2011 rates earlier this week, they emphasized that overall Medicare Advantage rates were falling an average of 1%, and that most enrollees who are now in a Medicare Advantage plans will continue to have access to Medicare Advantage plans, in spite of decisions by some major carriers to withdraw from the market.

Avalere Health L.L.C., Washington, a health care analysis firm, has analyzed Centers for Medicare & Medicaid Services premium data for another component of Medicare, stand-alone Medicare Part D prescription plans, and it says premium change figures for those plans depend heavily on the universe of plans considered.

The price of the most popular Medicare drug plan, AARP MedicareRx Preferred plan is falling 11%, to about $35 per month, but only 2 of the 9 next most popular plans are cutting prices, Avalere says.

The price of the 10 most popular Medicare drug plans will be increasing to about $39 per month, from about $35 per month, Avalere says. Those top 10 plans cover about 70% of Medicare prescription drug plan enrollees.

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