LOS ANGELES, CA (Catholic Online) - From 1990 to 2009, the number of hospital emergency departments declined by 27%, according to a study in today's Journal of the American Medical Association.

"That's a hefty number, and more than I expected," the study's author Renee Hsia says. An assistant professor of emergency medicine at the University of California-San Francisco, Hsia says she and colleagues did a "survival analysis," much like researchers do for breast cancer patients.

Hsia and her team found that the number of emergency departments dropped from 2,446 to 1,779, an average of 89 closings per year. "Certain hospitals are at higher risk for losing their ERs than others," Hsia says.

According to the study. ERs shut down were more likely to have low profit margins; serve patient below the poverty level; serve patients with poorer forms of insurance, including Medicaid; be located in for-profit hospitals; or be in more competitive markets;

Hsia says it's of major concern that during the same period of time that number of ERs has decreased, there's been a 35% increase in ER visits.

"The demand for care has increased and has rapidly outpaced our supply. They're going in opposite directions," she says.

Further studies indicate that the more crowded emergency departments become, the less able they are to give optimal care, and remain America's health care "safety net," she says.

"The ER is the bird's eye perspective of the whole healthcare system. If we really want a better system, not just band-aid solutions, we need to look at how to simplify the way we pay for health care," Hsia says.