Gender Gap May Be Narrowing in ACS Patients, With Mortality Advantage for Elderly Women

Among patients age 75 and younger with ACS, men and women have similar outcomes at 1 year, a signal that the gender gap has been attenuated, say Swiss researchers. After age 75, women appear to have a mortality advantage over men that is driven in part by a lower risk of CV death.

“Although we can only speculate about the reasons for improved long-term outcomes in elderly women as compared with their male counterparts, gender-related differences in the elderly have previously been attributed to a longer history of coronary artery disease in elderly men,” write Barbara E. Stähli, MD (University Hospital Zurich and University of Zurich, Switzerland), and colleagues. “In our patient cohort, elderly women were less likely to have known coronary artery disease and prior coronary revascularization and less frequently presented with left main or three vessel disease.”

The findings add to accumulating data refuting traditional thinking that female gender is associated with adverse outcomes after either an ACS event or PCI. Registry and database studies have attributed this poorer prognosis for women in part to “the overall increased cardiovascular risk profile in women and a less aggressive treatment approach,” Stähli and colleagues note.

Sorin J. Brener, MD (NewYork-Presbyterian Brooklyn Methodist Hospital), who was not involved in the new report, said while the study is reassuring that older men and women who are selected for revascularization seem to do well, it really only provides a piece of the picture with regard to outcomes in older people.

“What we need to know is what are the rates of events in patients presenting with ACS who are older than 75 and referred for revascularization, and then also what are the rates in those not referred for revascularization,” he said in an interview with TCTMD. “That is the critical piece that is missing. This was a select population of people referred for revascularization and does not reflect all older ACS patients.”

Elderly ACS Patients Doing Well but Undertreated

For the study, published online October 2, 2018, in Catheterization and Cardiovascular Interventions, Stähli and colleagues investigated the differences in outcomes among patients with STEMI, NSTE ACS, or unstable angina referred for angiography and enrolled in the Swiss ACS Cohort between December 2009 and October 2012. Older patients (> 75 years) were less likely overall to receive coronary revascularization than those age 75 or younger (P = 0.01). While revascularization rates did not differ between older men and women, younger women were less likely than their male counterparts to undergo revascularization procedures (P = 0.04).

At 30 days, the incidence of major adverse cardiovascular and cerebrovascular events (MACCE) was greater in those older than 75 years regardless of gender. However, the 1-year MACCE rates showed an interaction with age, with women having fewer events than men (15% vs 23%; P = 0.04), a difference that remained significant despite adjustments for baseline characteristics and extent of CAD. Rates of all-cause death at 1 year were much lower in the younger groups of men and women than the older groups, with mortality as high as 14% among men over age 75 versus 2.3% for men age 75 and younger.

CV mortality at 1 year was low and similar between men and women in the younger age group, but it was halved in women compared with men over age 75 (6% vs 12%; P = 0.02). No differences were seen in rates of TIMI major bleeding by age or gender.

Older patients were more likely than younger patients to be treated with clopidogrel or ticagrelor rather than prasugrel (P < 0.05). However, regardless of age, women were more likely than men to receive clopidogrel. While participation in cardiac rehabilitation programs was lower in patients over age 75 versus 75 or younger, cardiac rehab rates did not differ between men and women within either age group.

The researchers say the study also corroborates evidence from other studies that older patients have longer delays to revascularization than younger patients. Door-to-balloon time was 243 ± 430 minutes for patients over age 75 versus 178 ± 320 for those age 75 or younger. Similarly, symptom-onset-to-balloon time was 547 ± 541 minutes in the younger group compared with 733 ± 787 minutes in the younger group.

There was less use of glycoprotein IIb/IIIa antagonists in the older population, but no differences by age or gender in use of periprocedural antiplatelet therapy and anticoagulants. Another apparent difference, though, was that older patients were less likely than younger patients to receive statins, beta-blockers, or ACE inhibitors at discharge, and more likely to receive angiotensin receptor blockers.

“Although comorbidities, along with drug side effects and intolerance, may limit the use of certain medications in the elderly, these findings point toward a less aggressive treatment and less strict secondary prevention in the elderly and add to the evidence that certain age-dependent inequalities in medical care continue to exist,” Stähli and colleagues write. They suggest that more research targeted specifically at elderly cohorts is needed.

For his part, Brener agreed on the need for more data of this type, but noted that there has been a trend toward less exclusion of patients over age 75 for aggressive therapies in recent years that may not be reflected in the Swiss database due its age.

“Again, the real question is what happens to elderly people with ACS who are not referred for revascularization,” he observed. “In those cases, we see that women do not do as well as men because they are sicker in general when they are not referred, and the difference in outcomes compared with men is actually very large.”