Women diagnosed with myocardial infarction or unstable angina received “less evidence-based treatment” than men, both immediately and in the long term, found an Australian registry study published in Medical Journal of Australia.
The study showing “physician bias” in medical care, according to lead researcher and cardiologist Professor David Brieger at the University of Sydney.
The study found that Brieger said the treatment for such conditions differed between men and women “every step of the way”.
The study analysed a registry of 7,783 patients from 43 Australian hospitals who had been diagnosed between 2009 and 2018 either with unstable angina or non-ST elevation myocardial infarctions (non-STEMIs). Some 31% of these patients were female.
“Despite the way we think weʼre practising, we are still innately conservative and under-treating women for whatever reason,” added Brieger. “I think we have to be aware of that and consciously address it.”
Non-STEMIs are serious but less damaging than another type of heart attack, STEMIs, for which Australian women are half as likely to receive proper hospital treatment, previous research has shown.
A recommended procedure for patients with non-STEMIs is an angiogram, an imaging technique that identifies blockages in the coronary arteries. The study found a smaller proportion of women than men were given angiograms, and those who did tended to undergo them later.
“Weʼre not sure whether that reflects the fact that they presented to hospital later, or the decision to do the angiogram was delayed in some way,” Brieger said.
Women who have heart attacks can experience different symptoms to men – including nausea, sweating and generalised fatigue – and are more likely to have their cardiac events misdiagnosed. But, adds The Guardian, this study included only confirmed heart attacks, so misdiagnosis was not a likely factor for the differences in treatment.
There were also discrepancies in long-term medical care. “Once someone has come in with a coronary event they should all be discharged on evidence-based treatments,” Brieger said.
However, the team found that women were less likely to be prescribed various standard therapies, including aspirin, anti-platelet drugs, statins and beta blockers. Angiograms show that women tend to have less significant obstructions of their coronary arteries than men, Brieger said.
“That means theyʼre less likely to require stents and require a bypass. But we found they had a lower likelihood of receiving medical therapies. Surprisingly, even if they did have blockages, they still got less treatment.
“Even if we donʼt identify tight blockages in the arteries, we still know that women having these [heart attacks] are at n increased risk of having further events. Putting them on these medications will prevent these further events from happening.”
Women were also less likely to receive cardiac rehabilitation, “which is also very important in restoring them back to pre-event functional capacity and ensuring better longer-term outcomes”, he said.
Study details
Sex differences in the management and outcomes of non‐ST‐elevation acute coronary syndromes
Bianca C Bachelet, Karice Hyun, Mario D'Souza, Clara K Chow, Julie Redfern and David B Brieger
Published in Medical Journal of Australia 20 September 2021
Sex differences in the characteristics of acute coronary syndromes (ACS) have been described. Women present more frequently than men with non‐ST‐elevation myocardial infarction (NSTEMI), have atypical symptoms, more frequently have non‐obstructive coronary artery disease (NOCAD), and less frequently receive evidence‐based therapies.
In this study, we assessed differences in the evidence‐based treatment received by men and women with non‐ST‐elevation ACS (NSTEACS) and in their outcomes (in‐hospital and at 6‐month follow‐up). We also separately assessed these differences in patients with documented coronary artery disease (CAD).
We analysed Cooperative National Registry of Acute Coronary care, Guideline Adherence and Clinical Events (CONCORDANCE) registry data for patients diagnosed with NSTEACS (NSTEMI or unstable angina) in 43 Australian hospitals during 23 February 2009 – 16 October 2018. Patients with type 2 myocardial infarction were excluded. The clinical outcomes assessed were receipt of guideline‐based medications and invasive therapies, including cardiac catheterisation and revascularisation (percutaneous coronary intervention [PCI] or coronary artery bypass grafting [CABG]). In‐hospital outcomes were all‐cause deaths and major adverse cardiac events (MACE: cardiac death, myocardial infarction, stroke), adjusted for age group and comorbid conditions.
Procedures and outcomes at the 6‐month follow‐up were assessed by telephone interview. Our study was approved by the Sydney Local Health District Human Research Ethics Committee (CH62/6/2008‐141).
A total of 7783 patients were eligible for our analysis, including 2422 women (31%). Mean age was higher for women than men (67.9 years; standard deviation [SD], 14 years v 65.3 years; SD, 13 years), as was the median GRACE risk score (105.6; interquartile range [IQR], 82–129 v 100.8; IQR, 81–123). The proportion of women who underwent cardiac catheterisation was smaller (1710, 71% v 4134, 77%), and the median time to catheterisation was longer (53 h; IQR, 28–91 h v 47 h; IQR, 25–77 h); NOCAD was detected in a larger proportion of women than men during catheterisation (602, 35% v 566, 14%). At discharge, fewer women were prescribed aspirin (85% v 91%), a second antiplatelet medication (59% v 68%), β‐blockers (71% v 75%), or statins (86% v 92%), or referred to cardiac rehabilitation (54% v 63%)
A total of 4676 patients had documented CAD, including 1108 women (24%). Smaller proportions of women with CAD than of men underwent CABG (110, 10% v 563, 16%) or were prescribed statins at discharge (94% v 96%). Fewer women than men were referred to cardiac rehabilitation (750, 69% v 2652, 75%), including among those who had been revascularised (CABG: 97, 77% v 509, 83%; PCI: 480, 76% v 1623, 81%).
In multivariable analyses adjusted for hospital clustering and differences in baseline characteristics, adjusted mortality rates in hospital (adjusted odds ratio [aOR], 1.02; 95% confidence interval [CI], 0.71–1.46) and at six months (aOR, 0.85; 95% CI, 0.60–1.21) were similar for men and women, as were MACE rates in hospital (aOR, 0.97; 95% CI, 0.78–1.20) and at six months (aOR, 0.92; 95% CI, 0.75–1.14).
The women with NSTEACS in our study received less evidence‐based treatment, consistent with previous reports. The larger proportion of women with NOCAD may partly explain the difference. However, NOCAD is not a benign condition, and patients can benefit from secondary prevention therapies. In Australia, adherence to guideline‐based therapy for people with NSTEACS could be improved, especially for women in hospital and for both sexes at discharge.
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