Pneumonia patients often remain hospitalized longer than necessary, and a lot of money could be saved without compromising patients' health if they went home a day or so earlier, a new study suggests.

Pneumonia is one of the most common reasons for hospitalization in the United States, accounting for more than 600,000 admissions a year, researchers reported in today's Journal of the American Medical Association.Hospital stays among pneumonia patients vary considerably in different regions, different hospitals and even in different areas of the same hospital, previous studies indicate.

The variations remain even after accounting for differences in disease severity, other illnesses and hospital traits.

The new study looked at how long it took to stabilize 686 adults hospitalized with pneumonia at three university-teaching hospitals and one community hospital in Boston, Pittsburgh and Halifax, Nova Scotia.

Sixty-five percent to 86 percent of patients were kept at least a day longer than it took to stabilize them by vital signs. Fewer than 1 percent of patients became very ill again after stabilization.