WASHINGTON - Despite a recent easing of medical costs, the nation’s health care spending will keep outpacing economic growth for the foreseeable future, government specialists said Tuesday in a forecast that signals more upheaval for Medicare and Medicaid, as well as private insurance.

President Obama’s health care overhaul will add $478 billion in spending over the 2011-2021 period covered by the projections, expanding coverage to some 30 million uninsured people. But the issue of rising costs will not go away even if the Supreme Court overturns Obama’s law or his Republican foes ultimately succeed in repealing it.