An expected 2012 Medicare premium hike is smaller than expected. Monthly payments for some will actually be lowered, quashing fears that a coming 3.6 percent boost to Social Security benefits would be gobbled up by increased Medicare costs.

In 2012, the basic monthly premium for Medicare Part B, which covers doctor visits and other outpatient costs, will be $99.90, just $3.50 more than most beneficiaries have been paying since 2008, according to the Centers for Medicare & Medicaid Services (CMS). For new Part B enrollees, or those with a high income, premiums will drop from $115.40 per month to $99.90.

The Part B deductible in 2012 will be $140, down from $162, officials said.

Medicare Advantage plan enrollees' costs may differ. On average, these premiums will be 4 percent lower in 2012.

The U.S. government covers approximately three-quarters of the cost of Part B benefits, while monthly premiums cover the rest. About 44 million were enrolled in Medicare Part B in 2010.