Myth Busted? No Sex Differences in Typical
MI Symptoms

Megan Brooks

September 04, 2019

Women are more likely than men to have typical symptoms of myocardial infarction (MI) and these symptoms are more predictive of MI in women than in men, according to a new study from the UK that upends clinical dogma about sex differences in MI symptoms.

International guidelines currently state that women with MI commonly present with atypical symptoms, which goes against evidence from this study, say the researchers from the British Heart Foundation (BHF) Centre for Cardiovascular Sciences, University of Edinburgh, United Kingdom.

Incorrectly assuming that women with MI have different symptoms than men could lead to misdiagnosis, delayed treatment and less intensive treatment being offered, they note in a paper published online August 21 in the Journal of the American Heart Association.

"Our concern is that by incorrectly labeling women as having atypical symptoms, we may be encouraging doctors and nurses not to investigate or start treatment for coronary heart disease in women," first author Amy Ferry, BSc, cardiology research nurse at Edinburgh, said in a statement.

"Both men and women present with an array of symptoms, but our study shows that so-called typical symptoms in women should always be seen as a red flag for a potential heart attack," said Ferry.

Prior Studies Flawed?

While prior studies reporting sex differences in MI symptom presentation can boast large sample sizes, they are limited by the use of retrospective data collection from clinical records or patient registries of confirmed MI cases and therefore are at risk of selection bias, the researchers point out.

They prospectively recorded patient-reported symptoms in 1941 adults (1185 men, 756 women) with suspected acute coronary syndrome (ACS) seen in the emergency department at Edinburgh Royal Infirmary. 

Chest pain was the presenting symptom in 91% of men and 92% of women. Pain with "typical nature descriptors" (dull, heavy, tight, pressure, ache, squeezing, crushing, or gripping), the presence of radiation, and the presence of additional symptoms were all more common in women with suspected ACS (P < .04 for all).

Women with suspected ACS were more likely than men to report palpitations as a presenting symptom (11% vs 7%). Women were also more likely to report that their pain radiated to the left arm (36% vs 31%), the back (31% vs 17%), or to the neck or jaw (28% vs 20%), and to report associated nausea (33% vs 19%).

A total of 274 participants were diagnosed with type 1 MI, including 90 women (11.9%) and 184 men (15.5%). Diagnosis of MI was based on high-sensitivity cardiac troponin I assay with sex-specific thresholds (>16 ng/L women, >34 ng/L men).

Chest pain remained the most common presenting symptom for women and men with type 1 MI (93% and 93%). Women with type 1 MI reported pain with more typical nature descriptors than did men (81% vs 64%), and pain was classified overall as typical more commonly in women (77% vs 59%).

Less typical symptoms, such as epigastric pain, back pain, or pain that was burning, stabbing, or similar to that of indigestion were more common in men than women (41% vs 23%).

The second "major" finding, say the researchers, was that while individual typical pain features had a similar likelihood for predicting type 1 MI in women and men, the cumulative effect of between 1 and 4 typical pain features predicted MI more strongly in women than in men even after adjusting for baseline characteristics, including age and comorbidity.

Table. Risk for MI by Symptoms

# Typical Features

Odds Ratio in
Men (95% CI)

Odds Ratio in Women (95% CI)

0 or 1

1.0 ref

1.0 ref

2

1.1 (0.6 - 2.0)

4.0 (1.0 - 26.1)

3

1.5 (0.9 - 2.7)

5.9 (1.6 - 38.0)

4

1.8 (0.9 - 3.6)

6.9 (1.8 - 45.3)

Overall, the findings disagree with the contention in clinical guidelines that atypical symptom presentations occur more commonly in women. 

"We advocate that guidelines and educational material be updated to minimize the risk of underdiagnosis and treatment of women with myocardial infarction," Perry and colleagues conclude.

Important Study

Reached for comment, Colleen Coughlin, MD, cardiologist in the Women's Heart Program at Morristown Medical Center in New Jersey, said this study is "important because of its size and methodology, and its findings that women have typical symptoms, in contrast to current dogma."

"We need to be aware of symptoms, particularly clusters of symptoms [that] may improve diagnosis of [MI] in women in the emergency department," Coughlin told theheart.org | Medscape Cardiology. She was not associated with the current research.

"There is a need to encourage physicians to continue to take a thorough history in terms of the quality of pain, as well as associated symptoms, in women with suspected [ACS]. But additional confirmatory studies about typical and atypical symptoms should also be performed," she added.

The study was funded by the British Heart Foundation, the Edinburgh & Lothians Health Foundation, and NHS Scotland's Chief Scientist Office. Abbott Laboratories provided the troponin I assay reagents, calibrators, and controls without charge. Four authors reported financial relationships with Abbott Diagnostics. Coughlin has disclosed no relevant financial relationships.

J Am Heart Assoc. Published online August 21, 2019. Full text

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