JAMA Source Article | Comments Courtesy of Matt Zavadsky
Interesting study, and even more interesting (concerning) potential causes from the study authors. The accompanying editorial attempts to offer alternate reasons for the response time differences that are at least slightly more logical.
**Special Note: some of the terminology used relates to ambulance response time, but the average “EMS Response Time” indicated in the article of 37.5 minutes indicates this is the total EMS time – including transport to an ED. This is evident in the study, but not clear by the study title and editorial headline**
There seems to be two important take-a-ways from this research:
- There still appears to be an illogical assumption that faster ambulance response times equate to improved patient outcomes, something that has been refuted in numerous studies published in peer-reviewed journals.
- This study only looked at cardiac arrest cases, which represent a small % of overall EMS volume and a condition in which numerous factors other than ambulance response time has an impact (bystander CPR rates, AED use, 1st Responder response times, etc.)
- Many progressive EMS systems use the philosophy of on-scene stabilization prior to transport due to evidence-based research supporting this treatment modality.
- The researchers in this study do not seem to take that into account in the time analysis.
Poor communities wait longer for ambulances, causing health disparities
By Steven Ross Johnson | November 30, 2018
Patients that experience heart attack in low-income neighborhoods tend to wait longer for emergency medical services to arrive than those living in more affluent communities, a discrepancy that could drive health disparities between the groups.
Ambulances took an average of four minutes longer to handle calls from low-income areas than high-incomes neighborhoods, according to an analysis published Friday in JAMA Network Open that looked at more than 63,000 cases of cardiac arrest. The study marks the first national study evaluating disparities in 911 responses for cardiac arrest in high-income and low-income neighborhoods.
Researchers measured the time it took ambulances to arrive at a patient's location after it was dispatched, how long it took an ambulance on the scene to depart, how long it took to transport a patient from the scene to the hospital, and the total emergency medical services time.
The study found communities where the annual median income was between $57,000 and $113,000 had an average overall emergency response time of 37.5 minutes compared to 43 minutes in ZIP codes where the median income ranged from $20,250 to $42,642. Researchers also found EMS responses were more likely to meet nationally recognized benchmarks of arriving within eight minutes to a like-threatening event.
Study lead author Dr. Renee Hsia, professor of emergency medicine at the University of California San Francisco and an emergency physician at Zuckerberg San Francisco General Hospital and Trauma Center, said the findings help to show one of the many inequities that have contributed to the widening gap in health outcomes between poorer and wealthier Americans.
Research published in 2017 in Health Affairs found that 38% of people living in households with annual incomes of less than $22,500 reported to be in poor to fair health between 2011 and 2013 compared to just 12% of individuals making more than $47,000 a year.
"We've been talking about disparities for decades in the United States and a lot of time people think it because physicians might be biased, but this shows that there are systemic issues that we can do something about," Hsia said. "It's not just about training providers to be more culturally competent there are system-level biases that exists, and this is one of them."
Hsia said there were a number of potential factors that could contribute to the disparity in ambulance wait times.
She said it was possible that the spate of hospital, emergency department and privately-owned ambulance company closures in recent years could be a contributing factor for the longer wait times. Previous research has found EDs tend to have a higher closure rate in hospitals that regularly receive a high proportion of uninsured patients due to the low reimbursement they receive.
A 2014 Health Affairs study also authored by Hsia found the number of EDs in the U.S. decreased by 6% between 1996 and 2009. That study found one-quarter of hospital admissions between 1999 and 2010 occurred near an ED that had closed, which led to a 5% increase in the odds of mortality at those hospitals.
The study surmised closures could have led to longer EMS times because of the added strain it put on existing emergency departments that become more overcrowded, and lead to diverting ambulances more often to other facilities that increases transportation times.
But Hsia said another factor for the disparity in wait times could be related to the increase in recent years in the number of privately-owned ambulance companies that are contracted by local governments to provide services to their communities. More cities and towns have turned to for-profit ambulance providers to save money since those companies tend to bill commercial and public insurers or the patient directly for their services.
Hsia said it was possible that the shift in who's answering those emergency calls could be contributing to the disparity since companies would likely try to position their resources to better meet the needs of communities that are more likely to give the best returns.
Hsia said government EMS directors might benefit from looking more closely at whether the response times of ambulance providers they consider contracting with are distributed evenly across poorer and richer communities.
"I think that it's important policymakers realize that as there are these shifts going from publicly-funded entities that are providing these services to privately-funded entities that there may be different incentives that underlie their provision of these services," Hsia said.
Evidence has shown delays in ambulance response times can have a large impact on mortality rates. A 2001 study published in the medical journal BMJ concluded reducing ambulance response times to five minutes could almost double the survival rate for cardiac arrests.