For 35 years, Maryland has enjoyed a unique exemption from the federal government that allowed it to regulate hospital rates so that patients are charged the same no matter where they seek care. The state has come dangerously close to failing a test it must meet every three months to keep the exemption, under which the federal government gives Maryland larger Medicare payments than other states. To pass, the state must show federal officials that its Medicare costs have grown more slowly than in the rest of the country. For years, clearing that bar wasn't a problem, but that changed as healthcare costs in the state soared in recent years. The margin keeps narrowing and is all but nonexistent this year.