A study of 2,898 patients (2,183 men, 715 women) reveals that six months after hospital discharge, death rates and serious adverse cardiovascular events in women presenting with ST-Elevation Myocardial Infarction (STEMI) in the past decade were more than double the rates seen in men.
Sex differences in the management and outcomes of patients with acute coronary syndromes such as STEMI have been reported in the medical literature, but most studies fail to adjust for ‘confounding’ factors that can affect the accuracy of findings.
This new study, authored by leading cardiac specialists and researchers from across Australia, offers robust insights into this life-threatening condition by adjusting for factors that could affect treatment and health outcomes.
“We focused on patients with ST-Elevation Myocardial Infarction because the clinical presentation and diagnosis of this condition is fairly consistent, and patients should receive a standardised management plan,” said the University of Sydney’s Professor Clara Chow who is a cardiologist at Westmead Hospital, the study’s senior author.
“The reasons for the under-treatment and management of women compared to men in Australian hospitals aren’t clear.
“It might be due to poor awareness that women with STEMI are generally at higher risk, or by a preference for subjectively assessing risk rather than applying more reliable, objective risk prediction tools.
“Whatever the cause, these differences aren’t justified. We need to do more research to discover why women suffering serious heart attacks are being under-investigated by health services and urgently identify ways to redress the disparity in treatment and health outcomes.”
Professor David Brieger, co-author of the study and leader of the CONCORDANCE registry from which the findings were extracted, agrees: “While we have long recognised that older patients and those with other complicating illnesses are less likely to receive evidence-based treatment, this study will prompt us to refocus our attention on women with STEMI.”
A STEMI (heart attack) happens when a fatty deposit on an arterial wall causes a sudden and complete blockage of blood to the heart, starving it of oxygen and causing damage to the heart muscle.
A STEMI diagnosis is typically made initially by administering an electrocardiogram (ECG) that reveals a tell-tale ECG signature (see image below). These heart attacks can cause sudden death due to ventricular fibrillation (a serious heart rhythm disturbance) or acute heart failure (when the heart can’t pump enough blood to properly supply the body).
STEMI represents about 20% of all heart attack presentations. In 2016, an average of 22 Australians died from a heart attack each day.
Researchers collected data from 41 hospitals across all Australian states and territories between February 2009 and May 2016. Twenty-eight hospitals (68%) are in metropolitan regions and 13 are in rural locations.
Data was sourced from the CONCORDANCE (Cooperative National Registry of Acute Coronary care, Guideline Adherence and Clinical Events) registry, intended for use by clinicians to help improve the quality of patient care in line with treatment guidelines.
Main outcome measures: the primary outcome was total revascularisation, a composite endpoint encompassing patients receiving PCI (percutaneous coronary intervention), thrombolysis, or coronary artery bypass grafting (CABG) during the index admission.
Secondary outcomes: timely vascularisation rates; major adverse cardiac event rates; clinical outcomes and preventive treatments at discharge; mortality in hospital and 6 months after admission.
The average age of women presenting with STEMI was 66.6 years; the average age of men was 60.5 years.
More women than men had hypertension, diabetes, a history of prior stroke, chronic kidney disease, chronic heart failure, or dementia. Fewer had a history of previous coronary artery disease or myocardial infarction, or of prior PCI or CABG.
Objective: To examine whether there are sex differences in the characteristics, management, and clinical outcomes of patients with an ST-elevation myocardial infarction (STEMI).
Design, setting: Cohort study; analysis of data collected prospectively by the CONCORDANCE acute coronary syndrome registry from 41 Australian hospitals between February 2009 and May 2016.
Participants: 2898 patients (2183 men, 715 women) with STEMI.
Main outcome measures: Rates of revascularisation (percutaneous coronary intervention [PCI], thrombolysis, coronary artery bypass grafting [CABG]), adjusted for GRACE risk score quartile. Secondary outcomes: timely vascularisation rates; major adverse cardiac event rates; clinical outcomes and preventive treatments at discharge.
Results: The mean age of women with STEMI at presentation was 66.6 years (SD, 14.5 years), of men, 60.5 years (SD, 12.5 years). The proportions of women with hypertension, diabetes, prior stroke, chronic kidney disease, chronic heart failure, or dementia were larger than those of men; fewer women had histories of previous coronary artery disease or myocardial infarction, or of prior PCI or CABG. Women were less likely to have undergone coronary angiography (odds ratio, adjusted for GRACE score quartile [aOR], 0.53; 95% CI, 0.41–0.69) or revascularisation (aOR, 0.42; 95% CI, 0.34–0.52); they were less likely to have received timely revascularisation (aOR, 0.72; 95% CI, 0.63–0.83) or primary PCI (aOR, 0.76; 95% CI, 0.61–0.95). Six months after admission, the rates of major adverse cardiovascular events (aOR, 2.68; 95% CI, 1.76–4.09) and mortality (aOR, 2.17; 95% CI, 1.24–3.80) were higher for women. At discharge, significantly fewer women than men received β-blockers, statins, and referrals to cardiac rehabilitation.
Conclusion: Women with STEMI are less likely to receive invasive management, revascularisation, or preventive medication at discharge. The reasons for these persistent differences in care require investigation.
Ehsan Khan, David Brieger, John Amerena, John J Atherton, Derek P Chew, Ahmad Farshid, Marcus Ilton, Craig P Juergens, Nadarajah Kangaharan, Rohan Rajaratnam, Amy Sweeny, Darren L Walters, Clara K Chow