No one wants to make a repeat visit to the emergency room for the same complaint, but new research suggests it's more common than previously thought and surprisingly, people frequently wind up at a different ER the second time around.

Already some ERs are taking steps to find out why and try to prevent unnecessary returns. A Philadelphia hospital, for example, is beginning to test video calls and other steps to link discharged patients to primary care.

The new research, based on records in six states, suggests patients should be pushy about getting follow-up care so they don't have to return to crowded emergency departments.

"You need to make sure the next day, you connect the dots," said study co-author Dr. R. Adams Dudley of the University of California, San Francisco. "You cannot count on the health system to connect the dots."

It's also a reminder of how disconnected our health care system is. Chances are, your primary care doctor won't know you made an ER visit unless you call about what to do next.

And if your second visit was to a different ER, often doctors can't see your earlier X-rays or other tests and have to repeat them, adding preventable costs. While more hospitals and doctors' offices are trying to share electronic medical records, it's still far from common, especially in the fast-paced ER.

"It's frustrating. We're open 24 hours a day and we don't necessarily have access to those records," said UCSF assistant professor Dr. Reena Duseja, an emergency physician who led the research.

Hospitals are under pressure to prevent readmissions, when patients are discharged only to encounter problems during recovery that get them admitted again within a month. Less is known about how often patients who are patched up in the emergency room come back.

Duseja's team analyzed records from Arizona, California, Florida, Nebraska, Utah and Hawaii, among the first states to link records so patients can be tracked from one health facility to another. Researchers checked more than 53 million ER visits in which the patient was treated and sent home between 2006 and 2010, the latest available data.

About 8 percent of patients returned within three days, more than previous estimates, and 1 in 5 patients made a repeat visit over the next month, Duseja reported this month in Annals of Internal Medicine.

A third of revisits within three days, and 28 percent over a month, occurred at a different ER. Duseja couldn't tell why - if patients were dissatisfied the first time, or traveling, or for some other reason.

Patients with skin infections were most likely to return, followed by those with abdominal pain.

State rates varied a bit, with 6.2 percent of Arizona patients returning within three days compared with 9.3 percent in Utah.

Revisits may be appropriate, Duseja said. Nearly 30 percent of revisits involved hospitalization, suggesting either patients got worse or emergency physicians felt more scrutiny or testing was warranted.

Also, sometimes ERs tell patients to return - to see if an antibiotic is working, for example, or if they think the person can't or won't get follow-up care elsewhere. In the ER at San Francisco General Hospital, Duseja sees many Medicaid or uninsured patients who have trouble finding a primary care doctor or specialist.

ER workers sometimes make phone calls to help such patients secure appointments, said Dr. Rebecca Parker of Vista Health System in Waukegan, Illinois, who heads the American College of Emergency Physicians' board. When that doesn't work, "my choices are, do I send them to a clinic I can't get them into or bring them back to us?"

In Philadelphia, Dr. Kristin Rising of Thomas Jefferson University recently interviewed patients about why they returned to the ER, and found fear was a big motivator. Most had a primary care doctor. But they said they couldn't get an appointment quickly enough to answer lingering concerns, or didn't feel well enough for the multiple visits for X-rays or lab testing they were sure would be needed and that the ER could do under one roof.

Now Rising's ER is part of a hospital telemedicine program to explore if video calls address certain patients' concerns before they're up to a follow-up visit. In another pilot program, she said a contractor will call patients identified as at risk of returning, to help with next-step appointments.

This summer, the HealthShare Exchange of Southeastern Pennsylvania - a collaboration of care providers and insurers to electronically share patient information - will automatically send a summary of a patient's recent care to certain Philadelphia-area ERs when that person's insurance information is entered.

"We need to really think about, as a health system, how can we efficiently take care of our patients in the right place, at the right time," said UCSF's Duseja.