Women Less Likely Than Men to Survive or Get Life-Saving Therapy for Cardiac Arrest

More patients are surviving cardiac arrest today than a decade ago, but new data demonstrate that women still lag behind men in terms of survival, as well as in receiving angiography or PCI. 

“The fortunate thing is that we are making progress in improving outcomes,” lead author Luke Kim, MD, (Weill Cornell Medical College, New York, NY), said in an interview with TCTMD. “The bad news is there’s a discrepancy in care for women versus men. . . . [T]here’s still a substantial gap that we need to work on as clinicians, as well as the public in general, to optimize care in women when they present with cardiac arrest.”

Kim’s study, published online June 22, 2016, ahead of print in the Journal of the American Heart Association, examined data from the Nationwide Inpatient Sample on hospitalizations for cardiac arrest that occurred from 2003 through 2012 at 1,049 hospitals in 46 US states.

The annual incidence of arrests—cardiac, ventricular tachycardia/ventricular fibrillation (VT/VF), and pulseless electrical activity (PEA)/asystole—increased by 14% over the study period. The use of therapeutic modalities such as coronary angiography, PCI, and targeted temperature management (TTM) also increased during that time, but this uptick was several percentage points greater in men than in women. After adjusting for such factors as age, health, hospital characteristics, and previous cardiac procedures, women who had a cardiac arrest from a shockable rhythm were:

• 25% less likely than men to receive coronary angiography
• 29% less likely than men to undergo PCI
• 19% less likely than men to be treated with TTM

The rate of in-hospital death declined for both sexes (from 68.1% in 2003 to 59.6% in 2012) and separately for women (from 69.1% to 60.9%) and men (from 67.2% to 58.6%; P for trend < 0.001 for all). But over the study period as a whole, the rate was substantially higher for women than for men (64% vs 61.4%; P < 0.001). The difference was even greater among women versus men presenting with VT/VF arrest.

Compared with men, women had several phenotypic differences in presentation, including: older age, more comorbid conditions, less likelihood of preexisting CAD despite a greater prevalence of risk factors, and less likelihood of presenting with STEMI or a shockable rhythm.

“It’s evident that even when women present with treatable, underlying causes of cardiac arrest [they] are being treated less aggressively than men,” Kim observed. “Our study is in line with quite a few papers out there showing that women are not offered as many therapeutic options as men in these cases. Nor are they offered screening tests as frequently from their primary care doctors and others, which could detect a problem earlier.”

While teasing out the myriad of reasons why the gender gap exists will require more study, Kim and colleagues say prior studies suggest that women are less likely than men to have cardiac arrest witnessed by bystanders who could help, and tend to have less typical presentation prior to the arrest, which may lead to delays in treatment and misdiagnoses.

Time Is Survival

Commenting on the study for TCTMD, Gordon F. Tomaselli, MD (Johns Hopkins School of Medicine, Baltimore, MD), said the observed gender gap is not surprising and noted that even when the presentation is not exactly typical, physicians need to “keep their radar up” for cardiovascular causes of illness in women and treat more aggressively.

Another important point of the study and a message to the public, Tomaselli said, is that “time is survival, and meaningful survival that isn’t measured in hours, it’s measured in minutes and seconds when someone has a cardiac arrest.” Recognition and knowledge about what to do when someone collapses, in terms of improving circulation with bystander CPR, is a critical piece of the puzzle in improving outcomes, he added.

“This study reinforces the notion that we need to be on our guard and thinking about things that are treatable in women, because oftentimes we don’t,” Tomaselli said. “Despite the messages to the contrary, we still haven’t gotten that through to the provider community or to the public. Heart disease is a major killer of women, and in the acute circumstance, women should be treated in exactly the same way men are treated if we want to improve their survival.”

Paul S. Chan, MD (Saint Luke’s Mid America Heart Institute, Kansas City, MO), also commenting on the study, added many factors likely need to be teased out to understand why these differences are occurring.

“I find it hard to believe that physicians will make decisions about whether or not to treat based on the sex of the patient if that patient is eligible for that treatment,” he told TCTMD. “Having said that, we still see race-based differences in a lot of treatments.”

Flawed Conclusions?

But Chan noted that the majority of the literature has shown that women are actually more likely than men to survive in-hospital cardiac arrest. “We’ve also found that among people who survive to discharge from an in-hospital arrest, women are more likely to be alive at 1 and 3 years. Similarly, some have found that for out-of-hospital cardiac arrest, women are more likely to survive from the field to discharge,” he explained. “There are a lot of unanswered questions, in my mind, as to whether the data were able to accurately capture what they were looking at.”

Chan said that use of administrative data can lead to flaws in conclusions. Furthermore, the authors of the current study combined both in-hospital and out-of-hospital arrests but did not clearly differentiate those patient subsets. That is a problem, Chan said, because outcomes for these two tend to be dramatically different and if there happened to be a difference in the proportion of men and women in either group, it may explain some of the survival disparity.

In response, Kim noted, “It’s really hard to miscode a cardiac arrest, and the sheer number of patients we were able to capture [leads us] to believe the discrepancy we detected is significant. Plus, the gender differences were pretty clear cut. The discrepancy is large enough that we believe the findings are real.”

Tomaselli concurred. “If this were a one-off finding about undertreatment or underdiagnosis in women versus men I might be concerned it has something to do with the dataset itself, but this is consistent with other datasets that lead to the same questions and same concerns, which are that we are probably still not doing as good a job as we can with gender-specific diagnosis and treatment of cardiovascular disease.”