The nation's slumping economy is triggering growing Medicaid enrollment, according to state and national Medicaid experts. The trend could pose a challenge to states as they serve more uninsured people. "If the downturn is prolonged, and it contributes to large increases in Medicaid enrollment and spending, then this state and every other one will have to look at options to rein in spending," said Vern Smith, Michigan's former Medicaid director and coauthor of a report released by the Kaiser Family Foundation on Medicaid spending.