People who go into cardiac arrest in a high-income, mostly white neighborhood are nearly twice as likely to receive CPR from a bystander than those who suffer an arrest in a low-income, mostly black neighborhood.

That’s the upshot of a study published Wednesday in the New England Journal of Medicine. Researchers at the University of Colorado School of Medicine looked at data from 29 cities throughout the United States for 14,225 people who’d suffered cardiac arrest outside the hospital. They found that people who suffer an arrest in a neighborhood with a median household income of $40,000 or less and where blacks account for 80 percent or more of the population have a 35 percent chance of receiving CPR from a bystander, while a person who goes into arrest in a mostly white, high-income neighborhood has a 55 percent chance of receiving such aid.

The study further found that those whose cardiac arrest happened in a high-income black neighborhood were about 23 percent less likely to receive bystander-initiated CPR than those whose arrest occurred in a high-income neighborhood where most residents were not black.

Regardless of the neighborhood in which cardiac arrest took place, blacks and Hispanics were about 30 percent less likely than whites to receive bystander-initiated CPR, the study found.

Other key observations: People who received CPR initiated by a bystander were more likely to be male than female; they were more likely to be white than not; and their cardiac arrests more likely occurred in public than in private.

Even without accounting for neighborhood disparities, statistics regarding cardiac arrest and CPR are sobering. According to the study’s introduction, “More than 300,000 cases of out-of-hospital cardiac arrest occur in the United States each year. Outcomes of out-of-hospital cardiac arrest vary markedly, with survival rates ranging from 0.2 percent in Detroit to 16 percent in Seattle. This variation in survival rates can be explained, in part, by different rates of bystander-initiated cardiopulmonary resuscitation (CPR). On average, bystanders administer CPR during fewer than one third of all out-of-hospital cardiac arrests.”

In this study, 8 percent of the patients lived to be discharged from the hospital. Nearly 29 percent of patients in the study received bystander-initiated CPR.

The authors note that the cost of CPR training probably discourages people in low-income neighborhoods from seeking such training, and that language barriers and cultural norms among some minority communities may stand in the way of people learning and performing CPR. They suggest that their findings might help inform efforts on the part of organizations that promote and offer CPR training to better communicate their message in such communities.