Younger Women With STEMI More Likely Than Men to Die In-Hospital

Although STEMI patients—both men and women—younger than 60 years old are increasingly more likely to receive coronary revascularization, a study published in the November 3, 2015, issue of the Journal of the American College of Cardiology demonstrates persistent sex disparities. Specifically, middle-aged women with STEMI have a 1.5% greater chance of dying in-hospital.

“Despite years of educational efforts, there is still a perception of heart attack as a ‘man’s disease,’” Deepak L. Bhatt, MD, MPH, of Brigham and Women’s Hospital and Harvard Medical School (Boston, MA), told TCTMD in an email. “Women, their families, and hospitals all need greater awareness that heart attacks do occur in middle-aged women and that getting to the emergency room via an ambulance is the best way to ensure timely care, which most often includes angioplasty and stenting.”

Dr. Bhatt and colleagues examined Nationwide Inpatient Sample (NIS) data from 2004 to 2011 to assess temporal trends and sex differences in revascularization and in-hospital outcomes for younger patients with acute MI. The cohort consisted of 1,363,492 adults aged between 18 and 59 years (mean age approximately 50 years; 77.5% men). Of these, 632,930 patients (46.4%) had STEMI.

Compared with men in this age range, women with STEMI were slightly older and more likely to have CAD, congestive heart failure, and other comorbidities. However, they were less likely to be smokers or to have dyslipidemia, known CAD, family history of CAD, prior MI, prior PCI, prior CABG, or A-fib. Importantly, women were less likely than men to present with STEMI (adjusted OR 0.74; 95% CI 0.73-0.75).

Shifts in Care, Outcomes Seen

Although there were trends toward decreases in both the proportion and absolute number of STEMIs in both sexes, these shifts were associated with an increase in the absolute number of NSTEMIs over the study period (P < .001 for trend in women and men). There was also a decline in the average length of stay in both men and women over the study period (P < .001 for trend).

The use of PCI for STEMI increased in both younger men (from 63.9% to 84.8%; P < 0.001 for trend) and women (from 53.6% to 77.7%; P < 0.001 for trend) between 2004 and 2011. Yet overall younger women with STEMI were less likely than men to receive coronary angiography or any reperfusion. They also had higher rates of in-hospital mortality (primary endpoint) and longer lengths of hospital stay (table 1).

Additionally, there was a temporal increase in risk-adjusted in-hospital mortality from 2004 to 2011 in both younger men (OR 1.05 per year; 95% CI 1.04-1.06) and women with STEMI (OR 1.06 per year; 95% CI 1.05-1.07).

Many Factors at Work

Dr. Bhatt and colleagues say their findings of decreased STEMI in younger men and women, coupled with other NIS data “suggest that the proportion (and absolute number) of NSTEMI has increased in recent years in younger US adults, perhaps caused in part by more widespread use of sensitive cardiac biomarker assays resulting in more cases of unstable angina being classified as NSTEMI.”

The pattern of younger women being less likely than their male counterparts to receive revascularization follows that of the recent VIRGO study, they note. According to the authors, the reason for the disparity is likely multifactorial but may be explained by:

• Atypical presentation
• Delayed presentation and under recognition of STEMI at initial medical contact
• Higher frequency of alternative etiologies (ie, Takotsubo cardiomyopathy, spontaneous coronary artery dissection, and coronary vasospasm)
• Concern regarding increased risk of bleeding

Dr. Bhatt added that younger patients presenting with acute MI “can be particularly challenging, as the diagnosis is not always immediately considered.” This may be even truer in younger women versus younger men, he noted.

Potential for Database Obfuscation

In an editorial accompanying the study, Rashmee Shah, MD, MS, of the University of Utah (Salt Lake City, UT), and Noel Bairey Merz, MD, of Cedars-Sinai Heart Institute (Los Angeles, CA), write that the increase in risk-adjusted mortality in the face of increasing revascularization and decreasing length of stay “is counterintuitive and differs from other published data.”

While they say the finding may be true, Drs. Shah and Merz point out that administrative databases have the potential to introduce inaccuracies—ranging from diagnostic coding errors to the inability to fully capture or differentiate patient-level variables that could be predictive of mortality.

“These inaccuracies alone could account for the small incremental increase in risk over time,” they write.

Sources:
1. Khera S, Kolte D, Gupta T, et al. Temporal Trends and Sex Differences in Revascularization and Outcomes of ST-Segment Elevation Myocardial Infarction in Younger Adults in the United States. J Am Coll Cardiol. 2015; 66:1961-1972.
2. Shah RU, Merz CNB. Publicly available data: crowd sourcing to identify and reduce disparities [editorial]. J Am Coll Cardiol. 2015;66:1973-1975.

Disclosures:

• Dr . Bhatt reports research funding from Amarin, AstraZeneca, Bristol-Myers Squibb, Eisai, Ethicon, Forest Laboratories, Ischemix, Medtronic, Pfizer, Roche, Sanofi Aventis, and The Medicines Company.
• Dr. Shah reports owning stock in Gilead Science.
• Dr. Merz reports receiving contract and grant support from the National Heart, Lung, and Blood Institute, the National Institute on Aging, the US National Center for Research Resources,and the National Center for Advancing Translational Sciences; honoraria from Northwestern University, the Radcliffe Institute, and the University of California San Francisco; and consulting fees from Research Triangle Institute.

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