Sen. Charles Grassley (R-Iowa) on Tuesday slammed the Democrats over reports that Medicare Advantage (MA) plans are disappearing in Iowa.

"Seniors face fewer choices, fewer benefits and higher costs because of the partisan health care overhaul and previous changes to the Medicare program under Democratic leadership," Grassley said in a statement.

The comment comes in response to a Tuesday report in the Des Moines Register indicating that roughly 21,000 seniors enrolled in MA will have to find new coverage next year because companies are discontinuing some of their plans.

Though the state-specific figure is new, the idea that some MA plans won't be offered next year is not.

Last month, the Centers for Medicare and Medicaid Services (CMS) projected that about 5 percent of seniors in stand-alone MA plans would need to find new coverage because their current plans aren't renewing their contracts with the agency — largely the result of a 2008 law that put new restrictions on a particular type of MA plan dubbed private fee for service.

Affected seniors will have the choice of enrolling in another MA plan or shifting into traditional Medicare. Of the nearly 1 million seniors who fall into this category nationwide, about 2,300 will be forced into traditional Medicare because another MA option is not available, CMS estimated. Overall, MA enrollment is expected to increase by 5 percent next year.

Republicans have pounced on such reports, accusing the administration of walking back its vow that consumers, if they like their current plans, can keep them.

"The facts," Grassley said, "are indisputable."

Health and Human Services Secretary Kathleen Sebelius this week defended the Democrats' policies, arguing that the MA plans folding next year are doing so independent of the new health reform law.

"Any company that pulled out of the Medicare Advantage plan this year, my guess is that they had business plans to do that whether or not the president signed this law in March of 2010," she said.