Health insurance plans that for years offered enhanced Medicare coverage for 11 million Americans age 65 and older are under some strain.

Aetna Inc. has advised 8,500 area customers that it will terminate two of its Medicare Advantage plans at the end of this year. Independence Blue Cross has given the same notices to 44,000 individual subscribers who depend on four plans it offers.

Other insurers in other markets are also making cuts.

Meanwhile, area offices for the aging are being swamped with calls as worried senior citizens try to figure out whether their plans are affected.

"People are calling in tears," said Kim Andrews, director of a program with the Delaware County Office of Services for the Aging that helps the elderly sort out insurance options.

Both companies continue to offer other Medicare Advantage plans, and both also sell "Medigap" insurance, a supplement to Medicare.

"I'm upset, and so is my wife," said retired banker Joe McGough, 77, of East Falls, who received a letter from Aetna earlier this month.

"We haven't been that sick, and we're not costing them hardly anything," McGough said. "Maybe it has something to do with [President] Obama and all that health reform."

Health economist Mark V. Pauly at the University of Pennsylvania's Wharton School had a similar assessment. "Maybe they are just trying to tidy up before the storm," he said.

With Congress looking to Medicare savings to bankroll its plans for health reform, insurers around the country that sell Medicare Advantage plans are cutting back their offerings for 2010, saying federal reimbursements are too small.

Reimbursements for Medicare Advantage plans will be down 4 percent, the insurers said, even as medical costs for doctors and hospitals continue to increase.

"We had to take a hard look at our plans," said Eric Cormier, general manager of Aetna's Mid-Atlantic region and retiree markets.

Nationally, 24.2 percent of the 45.5 million people who qualify for Medicare use Medicare Advantage plans. Medicare is primarily federally funded health insurance, but its coverage has gaps.

Under Medicare Advantage programs, the government subcontracts with insurance companies to handle the paperwork, manage the care, fill in the gaps, and provide various extra services, such as drug and dental plans. The insurers also charge premiums and co-pays.

The federal government pays the insurers an average of 12 percent more than it would cost to fund plain-vanilla Medicare. Reimbursement varies by county, depending on costs.

Rural areas usually get more, and Medicare also provides reimbursements to hospitals handling caseloads of poor patients who cannot pay.

But policymakers in Washington have been looking at that extra reimbursement, seeing it as part of the way to fund increased coverage.

A Congressional Budget Office analysis of the Senate Finance Committee bill sees $404 billion of the $829 billion 10-year price tag coming from savings in Medicare and two other programs. An earlier analysis suggested that Medicare changes would provide 10-year savings of $460.3 billion. Of that, $124.3 billion would come from changes to the Medicare Advantage plans.

In a House version of the bill, Medicare Advantage savings would amount to $172 billion over 10 years, according to an analysis by the Kaiser Family Foundation.

Pauly said Medicare Advantage plans were caught in an ideological shift. Democrats would like to see private insurers out of the Medicare business, he said. "Payments have been reduced, and they are on the chopping block going forward."

Medicare, he said, "is both the model and the stalking horse for single-payer insurance."

Despite the cuts, insurers want to stay in the senior-citizen market, especially in a state such as Pennsylvania, with its large elderly population.

"The demographics are there," said Jason Feuerman, senior vice president and executive director of Bravo Health Pennsylvania in Philadelphia. Bravo is a Maryland-based company that sells only Medicare Advantage plans, specializing in HMO coverage. It is expanding its local reach.

In the Philadelphia area, cuts by Independence Blue Cross affect just over a third of its 133,500 individual Medicare Advantage subscribers.

Aetna is eliminating plans covering 6,500 individuals in Philadelphia and its suburbs, or 19 percent, and 1,000 in nearby New Jersey counties, or about 12 percent.

Both insurers are eliminating plans that serve elderly subscribers poor enough to qualify for Medicaid. Aetna's plan serves 1,000; the Independence Blue Cross plan serves 19,000.

These are the main plans to be cut: Aetna's Medicare Golden Premier PPO plan and Independence Blue Cross' Keystone 65 Complete, Keystone 65 Value across the region, and Personal Choice PPO 65 for subscribers in Chester, Delaware, and Montgomery Counties.

In Philadelphia and Bucks County, Independence Blue Cross' Personal Choice PPO 65 plans will continue.