California Study Shows Potential Dangers of Ambulance Diversion

Heart attack patients are more likely to die within one year if they were diverted from a crowded emergency department to a hospital ED farther away, according to a study published this month in Health Affairs, Kaiser Health News reports.

For the study, researchers from the University of California-San Francisco and the National Bureau of Economic Research reviewed ambulance diversion data on about 30,000 Medicare beneficiaries in 26 California counties between 2001 and 2011.

Study Findings

Overall, about half of heart attack patients were diverted on the day they were admitted. California's counties have varying policies on ambulance diversion, and some counties were more affected than others, according to KHN. For example, in Los Angeles County, about 75% of heart attack patients were diverted during some years of the study period.

The researchers found that the death rate for heart attack patients after one year was about 10% higher among those who had been diverted.

In addition, patients who had been diverted were slightly less likely to have received treatment -- such as an angioplasty or coronary artery bypass graft -- necessary to restore blood flow to major organs. According to KHN, this was largely because the hospitals receiving the patients had less-advanced cardiac care technology.

Further, the researchers noted that racial and ethnic minorities were more likely than other patients to be diverted.

Meanwhile, ambulance diversions decreased throughout California over the study period. For example, diversions at the LAC+USC Medical Center, one of the busiest EDs in Los Angeles County, dropped from an average of 62% in 2011 to 32% in 2014. According to KHN, Los Angeles County in 2006 established measures to prevent hospitals from automatically remaining on diversion status for several hours at a time.

Reaction

The findings add to a growing collection of research showing the harm of diverting ambulances for patients with life-threatening conditions, KHN reports. For example, a smaller study conducted in New York City also connected ambulance diversion to higher heart attack death rates. In addition, other studies have noted that diversions result in the delayed administration of drug therapy to heart attack patients.

Renee Hsia, a UC-San Francisco researcher and study co-author, said, "This study is telling us that as we continue to saturate our emergency care system, (diversions) affect everybody. We tend to think that it's only people who aren't that sick who don't get treated quickly in emergency rooms. Diversions affect patients who are really sick, too."

Meanwhile, the California Ambulance Association's Ross Elliott said, "Diversion is essentially a crutch that allows hospitals to understaff and not make efficient use of all the resources they have." However, he also noted that diversions help reduce the amount of time paramedics wait at a hospital for patients to be admitted. "It still boils down to lack of resources to meet the demand," he said (Feder Ostrov, Kaiser Health News, 8/31).