Community factors linked to cardiac-arrest outcomes

A study of people who had suffered out-of-hospital cardiac arrests showed that their locations affected their outcomes: 

• People in rural areas were less likely to have been resuscitated by the time they reached the emergency department than were those in poorer urban areas.
• People in economically deprived urban areas who made it to the hospital were less likely to survive, or had worse neurological outcomes, than those in urban areas that are more well-off.

The findings, from researchers at the University of Washington School of Medicine, are published in JAMA Network Open.

“People have assumed that if we just improve EMS, we will eliminate the differences in outcomes we see between one community and another,” said senior author Dr. Graham Nichol, professor (General Internal Medicine) and emergency-medicine expert at UW Medicine.

“What we showed is that that may not be the case, and that we may need to think about nonclinical interventions. These might include better healthcare access, better health insurance or better wages. We cannot say exactly what needs to be done, but these nonclinical factors can't be ignored.”

In recent years, survival rates among people who suffer an out-of-hospital cardiac arrest have improved, largely due to improvements in emergency medical systems (EMS) care. Nevertheless, only about 1 in 4 people who suffers a cardiac arrest outside of a hospital and who receives EMS care survives and is admitted to the hospital.  Only about 1 in 10 lives and is discharged from the hospital.

All told, more than 350,000 Americans who receive EMS care after out-of-hospital cardiac arrest die every year — nearly 1,000 a day.

Previous research has shown that outcomes can differ greatly from region to region, even after taking into consideration the patients’ age and health and the type of care the EMS technicians provide.

To help identify the factors that might account for differences in survival and outcome seen between communities, researchers compared outcomes between rural and urban areas and  took into account the level of poverty in the communities where the patients lived.

The poverty of an area was based on a statistic that factors in an area’s resources, income, education and housing status, called the Area Deprivation Index. The researchers use this index to categorize areas as low-, moderate- and high-deprivation.

The researchers looked at two main outcomes: 

• First, whether the patient arrived at the emergency department with “spontaneous circulation” —  that is, their hearts had resumed beating and were maintaining adequate blood pressure. 
• Second, whether the people survived to be admitted to the hospital, the outcome of their hospitalization (whether they survived to be discharged and, if so, where they were discharged to: their home, a nursing facility, a rehabilitation facility or a hospice).

Where they went after leaving the hospital was used as an indication of their neurological condition upon discharge, with discharge to their home suggesting the best neurological outcome. Discharge to a nursing home, a rehab facility or a hospice were indicators of progressively worse neurological outcomes.

They found that, compared to patients from urban areas with low deprivation, patients from rural areas, regardless of the degree of neighborhood deprivation, were significantly less likely to arrive at an emergency department with spontaneous circulation.

On the other hand, among patients who survived to hospital admission, those from urban communities with moderate or high poverty were less likely to survive to hospital discharge than those from more affluent urban communities, and, if discharged, those patients from poorer neighborhoods were likelier to have worse neurological outcomes.

“The patients were similar and appear to have received the same level of emergency care, so clinical factors may not be driving the large differences we see in outcomes,” said first author Dr. Lakota Cheek. “Our findings suggest that nonclinical factors need to be addressed to improve outcomes for these patients.”

Cheek conducted the research while he was a UW Medicine emergency medicine resident. He is now a fellow at the University of Colorado Anschutz Medical Campus.