In another sign of the economy’s toll on the nation’s health care system, some hospitals say they are seeing fewer paying patients  even as greater numbers of people are showing up at emergency rooms unable to pay their bills.

While the full effects of the downturn are likely to become more evident in coming months as more people lose their jobs and their insurance coverage, some hospitals say they are already experiencing a fall-off in patient admissions.

Some patients with insurance seem to be deferring treatments like knee replacements, hernia repairs and weight-loss surgeries  the kind of procedures that are among the most lucrative to hospitals. Just as consumers are hesitant to make any sort of big financial decision right now, some patients may feel too financially insecure to take time off work or spend what could be thousands of dollars in out-of-pocket expenses for elective treatments.

The possibility of putting off an expensive surgery or other major procedure has now become a frequent topic of conversation with patients, said Dr. Ted Epperly, a family practice doctor in Boise, Idaho, who also serves as president of the American Academy of Family Physicians. For some patients, he said, it is a matter of choosing between such fundamental needs as food and gas and their medical care. “They wait,” he said.