Minority and low-income seniors were more concentrated among Medicare Advantage plans than they were in the overall Medicare program, according to an industry analysis of CMS data.

The analysis (PDF) of the 2010 Medicare Current Beneficiary Survey access to care files for noninstitutionalized beneficiaries, released Thursday by America's Health Insurance Plans, found that 26% of the program's participants enrolled in private Medicare Advantage plans.

However, minority enrollment in the private insurers included 29% of African-American beneficiaries and 36% of Hispanic beneficiaries.

Similarly, while 39% of overall Medicare beneficiaries had less than $20,000 in income that year, 43% of enrollees in the private plans had such low incomes.

The report also highlighted that 64% of all racial minority enrollees in Medicare Advantage plans had incomes of less than $20,000 and only 39% of white enrollees in the private plans had incomes such low incomes.

Such private Medicare insurance plans have faced longstanding criticism from Democrats for contributing to the program's spiraling costs because they charge more for each beneficiary than the average beneficiary in the basic Medicare plan. Defenders of such plans have historically argued that the higher costs came with more benefits and better outcomes for their enrollees.

The latest data could indicate that low-income minority enrollees are helping to drive the growth of such plans, which have increased their enrollments by 17% since 2010, according to an HHS report in February. That growth came despite insurance industry representatives' stated fears that such plans would wither as cuts required by the 2010 federal healthcare law are implemented. The largest such cuts are slated to begin in 2015, according to the industry.