Survival rates for black women after bystander CPR are far lower than for white men, according to a study published this month in the American Heart Association’s journal Circulation.

The study shows a disturbing discrepancy in the effectiveness of bystander resuscitation for cardiac arrests that occur out of a hospital. While bystander resuscitation generally improves survival rates, its benefit is significantly lower for black people and women, according to the study.

The study examined more than 623,000 patient records and found that nearly 40% of people who suffered cardiac arrest outside of a hospital were resuscitated by a bystander. Bystanders are defined in the study as non-professional helpers such as family members or passersby. According to the American Heart Association, resuscitation can be performed by giving simple, strong and quick chest compressions, doubling or tripling a person’s chances of survival.

Dr. Paul Chan, a cardiologist at Saint Luke’s Mid America Heart Institute in Kansas City and lead author of the report, told CNN the goal of the study was not to prove what was already known: that people of color are less likely to receive CPR. Rather, it was to answer a twofold question: Was CPR initiated by a bystander, and does the patient receive the same benefit regardless of gender, race or ethnicity?

“It’s not just about getting people to start CPR, but about doing it as effectively and well as possible in all groups of people,” Chan told CNN.

The study found that patients who received bystander CPR had, on average, a 28% higher chance of survival than patients who did not receive CPR.

However, survival rates varied considerably by race and gender. White men who received bystander CPR had a 41% higher chance of survival than men who did not receive CPR, while black women fared the worst, with only a 5% higher chance of survival than men who did not receive CPR.

The study suggests “that differences in dispatcher training and resources may lead to lower quality dispatcher instructions for CPR in black communities.” The authors also point to low rates of CPR training in communities of color. Both factors may contribute to differences in survival rates.

However, the study notes that “further research is needed to determine why the association between bystander CPR and survival is weaker among blacks and women.”

Chan called the results “alarming.”

“If we think about someone with cancer and let’s say there is a very effective treatment for breast cancer or colon cancer. We worry about whether there are disparities in starting cancer treatment, if women or black people are less likely to get effective chemotherapy or treatment. But would we also be concerned if the benefit for certain groups of people is much smaller when that treatment is started?” he asked.

“The difference between bystander resuscitation and drug treatment is that drugs can be standardized. You get a certain dose of, say, chemotherapy – 50 milligrams – and everyone gets 50 milligrams. But with resuscitation, the quality and type of intervention can vary greatly depending on who’s doing it.”

Chan says some people may be uncomfortable performing CPR on a woman because the dolls used in official CPR typically do not have breasts.

Jade Calvin, a paramedic with Bell Ambulance in Milwaukee, has been a dedicated emergency medical services professional for nearly eight years and now works in the education department as a first aid instructor, teaching new protocols.

“People are more hesitant to perform CPR on women,” Calvin told CNN. “It’s more socially acceptable for men. It’s normal for them to have their chest exposed, but it’s not normal for women. So when they do perform CPR, people are afraid because they want to protect the woman’s modesty.”

Calvin also noted that when resuscitating women, there is often a fear of effective CPR. “They always say you should push hard and fast,” she said. “However, society generally believes that women are more petite and fragile than men, so they are afraid of more effective CPR.”

“You’re going to break ribs. It’s OK,” Calvin said. “You just push hard and fast. Someone will take over soon.”

Chan says it’s harder to understand racial differences in the use of bystander CPR.

“We looked at the benefit of bystander CPR when the victim collapsed in the black and Hispanic community,” he said. “The only group that didn’t benefit was black people in black and Hispanic communities.” Chan said the quality of CPR isn’t necessarily always worse in black and Hispanic communities, “because we don’t see that when Hispanic and white individuals in those communities receive bystander CPR.”

Chan says the American Heart Association and the American Red Cross have significantly increased their efforts to promote CPR in traditionally underserved communities. These communities are now the focus of increased outreach and education initiatives to address longstanding disparities.

As Calvin reflected on her experience, she noted that when she first started working in the emergency services, she was often the only woman or the only person of color in the workplace. She stressed the importance of ensuring that participants in the training are representative: “It’s important that people see people who look like them in these trainings.”

Calvin is optimistic about the growing diversity in the field. “Little boys and girls see people who look like them saving lives. It makes them want to do the same.”

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