If you feel like your managed care headaches continue to grow, it's likely because Medicare Advantage enrollment is growing too. "Enrollment and spending in Medicare Advantage (MA) plans ... have more than doubled since 2004," the Government Accounting Office says in a new report. Enrollment in the MA plans the GAO analyzed increased by about 6 percent, from 7.9 million to 8.4 million beneficiaries, from April 2010 through April 2011. One reason for the increase may be that the average monthly premium for beneficiaries in MA plans decreased from $28 in 2010 to $24 in 2011, about a 14 percent reduction, the GAO notes in the report at at www.gao.gov/products/GAO-12-93.