Exposing the bias in biology: heart disease in women

Special feature with BHF Scotland

Mirren Robertson was out having a meal in San Francisco with her son at the end of a visit to see him and they began walking up one of the city’s famously steep hills when she suddenly walked into a brick wall. Or at least that’s what it felt like.

“There was no pain, it was discomfort, and it was as if I was trying to walk through this wall,” Mirren tells Holyrood. “It was the weirdest feeling – it was a physical slowing down, it was as if I was walking into a brick wall, and there was a pressure on my chest.”

Six weeks later, back in Scotland, Mirren says she felt “I still wasn’t right”.

“And I said to myself, if one of my pals had described this, I would have been saying something like: ‘And what did your GP say about it?’ I thought, wait a minute, listen to myself, I need to see my GP.”

Mirren’s doctor was quick to diagnose her with angina, a heart condition caused by a restriction in blood supply to the heart, and she was prescribed angina medication, a glyceryl trinitrate (GTN) spray.

However, something still wasn’t right. The first time she used the GTN spray at home she felt “the most severe ice-cream headache you could imagine”. “It was as if an axe murderer had come in and sliced my head, from the top of my head to my chin,” she recalls.

And then one day, Mirren used the spray after rushing to the station to board a train to London, but she blacked out.

“What it does is it lowers your blood pressure and with me, it did it so dramatically that I fainted,” she says. “I woke up and I felt, ‘what the heck’ and I was going to be travelling to London and I thought, is it safe to travel to London?”

Understandably, Mirren stopped using the medication.

She was sent for further tests and then referred to Golden Jubilee National Hospital, where she was asked whether she’d like to sign up for a research programme.

“I said, yes, I will sign up, because I recognised that they would be working to find out what was wrong with me,” Mirren says. “The research programme lasted a full year. Because I was willing to take part in this research, I had extra tests, urine tests, blood tests, questionnaires and so on.

“What was really important to me was I was told I had microvascular angina, which is treatable. That was just so lovely, to have a name for this thing and to be told it was treatable.

I was put on the appropriate medication and I just bounced back into, let’s get going, life is good I’m a happy puppy and I haven’t stopped going since then

Microvascular angina results from an abnormality of the tiny arteries in the heart muscle, which play a key role in regulating blood supply to the heart. But the small vessels are not visible in angiograms, an X-ray that examines blood vessels, which can make it difficult for health professionals to spot.

Heading up the Golden Jubilee research programme is Professor Colin Berry, the hospital’s director of research and development, and a consultant cardiologist at Queen Elizabeth University Hospital.

Berry tells Holyrood that in Scotland “we are experts in dealing with blocked coronary arteries” but the majority of patients who have blocked coronary arteries are men.

“It’s a male phenomenon,” he explains. “We have great tests to identify obstructive coronaries in mostly men, but we are less well placed to make positive diagnoses and positive treatments for women with angina and heart attacks due to small vessel problems.

Three-quarters of the affected patients are women and we’re just starting to understand this

The British Heart Foundation (BHF) Scotland’s Bias and Biology policy report reveals that every year, one in ten Scottish women die from ischaemic heart disease (IHD), which includes heart attacks and angina. That’s seven women every day.

A roundtable discussion on the future for heart disease

Women have a worse survival rate from heart disease than men, but in a survey conducted by BHF Scotland, of 1,000 Scottish women, 83 per cent did not think this was the case.

Further, smoking, diabetes and high blood pressure increase the risk of a heart attack more in women than men, but only 15 per cent of the survey respondents believed that was true.

In the same survey, women reported being more concerned about their risk of developing breast cancer than heart disease – despite BHF statistics showing heart disease kills nearly three times as many women as breast cancer.

Berry’s interest in the gender disparity of heart disease was piqued during an earlier study at Golden Jubilee with BHF Scotland.

“My dialogue just now is different than five years ago, because of the research we’ve done,” he explains.

He says 391 patients were enrolled for the study, all of whom had undergone angiograms, but the results showed they did not have blocked arteries. When the researchers measured the small vessel function of those with clear coronary arteries, “three-quarters of them were women”.

“It was a randomised trial, we were looking at, if we made measurements of small vessel function and we disclosed those results to the clinician at the time of the angiogram, does that change their diagnosis?

“But when we actually looked at the patients who got into the study, most of them were women.”

Asked why the small vessel issue in women is not always being detected, Berry says there are a few issues: around the testing currently available for smaller blood vessels, a lack of data differentiating between each gender’s experience with heart disease and a lack of awareness.

Berry says cardiology is “imbued with bias” and it had historically been populated “by white males like me”.

“And we have tools at our disposal that are better at picking up the problem in men than women,” he says.

The bias is that the clinicians are trained to think about the male problem, the tests and the treatments they have track with the male problem

“More men die from IHD than women, but at an individual patient level, I am concerned that a woman with angina or a heart attack may be less well placed to have health equity in that care process in the context of cardiology.”

Another issue: “The treatments available for IHD have been developed preponderantly in male populations.

“In medicine, we’re only as good as what we know, and we’re only as good, as effective in healthcare, as the tools that we have at our disposal,” he says. “Governments, healthcare providers like the NHS, have been effective in driving down deaths from ischaemic heart disease – it’s a big success, but it’s flatlined now.”

Berry adds that he is seeing more young women coming into hospital with heart problems.

“That is the real concern. A younger woman, she may be a mother, she might have several jobs, she may be less able to comply with cardiac rehabilitation, and in some of the public health information, they’re stereotyping for heart disease in men,” he says.

“In terms of communicating about stopping smoking, fitness, if you have preponderantly images of men in those images, the message isn’t going to be so well received, or it will perhaps be ignored, by women.”