The number of U.S. adults who had health insurance all year but were still "underinsured"—with very high medical expenses relative to their incomes—rose by 80 percent between 2003 and 2010, from 16 million to 29 million, according to a new Health Affairs study by The Commonwealth Fund's Cathy Schoen, Michelle Doty, Ruth Robertson, and Sara Collins. The Affordable Care Act, once fully implemented, could help reduce the number of underinsured Americans by as much as 70 percent, the authors say.
