Hospital emergency rooms, particularly those serving the urban poor, are closing at an alarming rate even as emergency visits are rising, according to a report published on Tuesday. Urban and suburban areas have lost a quarter of their hospital emergency departments over the last 20 years, according to the study, in The Journal of the American Medical Association. In 1990, there were 2,446 hospitals with emergency departments in nonrural areas. That number dropped to 1,779 in 2009, even as the total number of emergency room visits nationwide increased by roughly 35%. Emergency departments were most likely to have closed if they served large numbers of the poor, were at commercially operated hospitals, were in hospitals with skimpy profit margins or operated in highly competitive markets, the researchers found.