Cardiac arrest—when the heart suddenly and unexpectedly stops beating—is fairly common among hospitalized patients, affecting approximately 200,000 patients in the U.S. each year.
Historically, the likelihood of surviving an in-hospital cardiac arrest was low—roughly one in eight patients would live long enough to be discharged. Among black patients, the survival rate was even lower than that of white patients, according to previous research.
Over the past 15 years, however, survival of in-hospital cardiac arrest has improved considerably, particularly at hospitals participating in a nationwide evidence-based quality improvement program called Get With the Guidelines–Resuscitation, established by the American Heart Association (AHA). And as overall patient survival has improved, differences in the survival rates among black and white patients have narrowed as well, according to a new study led by University of Iowa Health Care researchers.
“Racial disparities in health care in general, and with in-hospital cardiac arrest in particular, have been well documented in the medical literature,” says Lee Joseph, postdoctoral research fellow in cardiovascular disease in the UI Department of Internal Medicine and lead author of the study published in the Aug. 9 issue of JAMA Cardiology. “But as overall survival of in-hospital cardiac arrest improved over the past decade or so, it raised the question: Are these improvements benefitting black and white patients equally?”
Saket Girotra, assistant professor in the Division of Cardiovascular Medicine in the UI Department of Internal Medicine and the study’s senior author, says earlier studies have found that racial disparities are closely linked with hospital quality.
“For in-hospital cardiac arrest, black patients have lower rates of survival than white patients not because they’re treated differently in the same hospital—it’s more the case that black patients tend to be overrepresented in lower-quality hospitals,” Girotra says. “In our study, we were interested in determining whether improvements in hospital quality over time have been accompanied by a reduction in racial differences in survival for in-hospital cardiac arrest.”
Using data from the AHA’s Get With the Guidelines registry, Girotra, Joseph, and colleagues studied data from more than 112,000 patients (30,241 black and 81,898 white) at 289 hospitals who had experienced in-hospital cardiac arrest between 2000 and 2014.
After adjusting for factors such as age, gender, preexisting conditions, medical interventions before the cardiac arrest, and characteristics of the cardiac arrest itself, the researchers found that in 2000, white patients had a survival-to-discharge rate of 15.8 percent; by 2014 it had improved to 23.2 percent. Black patients in 2000 had a survival-to-discharge rate of 11.3 percent; in 2014, the rate was 21.4 percent.
“Over the course of the study, not only did the survival rates for both black and white patients increase, but the gap between the two groups narrowed considerably—a 4.5 percent racial gap in 2000 was lowered to 1.8 percent by 2014,” Joseph says. “That’s a notable achievement for hospitals participating in the (Get With the Guidelines–Resuscitation) registry.”
The research team also examined whether hospitals that disproportionately treat black patients had achieved larger improvements in survival over time; such hospitals are known to have lower survival rates. In this study, hospitals with a higher proportion of black patients in 2000 had lower rates of survival compared to the hospitals with a lower proportion of black patients. Both groups of hospitals improved over time, but the hospitals with higher proportions of black patients made much larger gains, which likely accounts for the narrowing in the gap between black and white patients by 2014.
In a hospital setting, survival from cardiac arrests depends on two phases. During the acute resuscitation phase, medical personnel perform CPR or other interventions such as defibrillation in order to bring back the patient’s pulse. However, even after the patient has regained a pulse, they remain at risk from permanent brain damage or other complications from changes that occurred in the body when the heart had stopped.
The research team did not have information on what hospitals did specifically in terms of resuscitation care nor how hospitals used data from the registry to implement changes in care. However, they found that most improvements in survival and reductions in racial disparities over time occurred during the acute resuscitation phase, when factors such as the identification of cardiac arrest, timeliness and quality of chest compressions, and the need for defibrillation in certain cases are key.
“Over time, improvement in survival during the acute phase improved in both black and white patients to the point that differences between black and white patients that were present at the beginning of our study period were completely eliminated by the end of the study period,” Girotra says. “Differences persisted, however, between black and white patients in regard to the post-resuscitation phase. These findings provide some clues as to what may have led to the reduction in racial differences that we observed.”
Girotra and Joseph note that the study did not examine survival rates of in-hospital cardiac arrest at hospitals not participating in the Get With the Guidelines registry. But within the context of their study, the findings should bolster ongoing quality improvement programs, such as the registry, to continue to advance their work.
“Unlike previous studies that have shown a reduction in racial differences in treatments or care delivery, our study showed a reduction in racial differences in an outcome measure—survival,” Girotra says. “Demonstrating improvement in survival differences by race makes our findings even more impactful.
The study was funded by the National Heart, Lung, and Blood Institute of the National Institutes of Health. The AHA, which supports the Get With the Guidelines programs, had no role in the design, implementation, or analysis of the study.
Study co-authors include Paul Chan and Philip G. Jones, both from Saint Luke’s Mid America Heart Institute and the University of Missouri, Kansas City; Steven Bradley, from the Minneapolis Heart Institute, Minneapolis; Yunshu Zhou, from the Institute for Clinical and Translational Science at the UI; and Mary Vaughan-Sarrazin, from the UI Department of Internal Medicine.