More than 1 million patients will remain uninsured because they live in 24 states that chose not to expand Medicaid under the Affordable Care Act, according to a study released Friday by researchers at George Washington University. Most of those patients live in the South, because every state in that region except Arkansas and Kentucky opted against expanding the federal-state program for the poor after the Supreme Court ruled in 2012 that it was optional. Gaining coverage helps health center patients get access to specialists along with prescription drugs, diagnostic tests and hospital care for little or no out-of-pocket costs.