Doctors are failing to diagnose women with a potentially deadly heart condition because tests rely on outdated studies from the 1970s and do not account for natural differences in sex and body size.
Hypertrophic cardiomyopathy (HCM) is a genetic condition where the muscular wall of the heart becomes thickened, making it harder for the heart to pump blood around the body. It affects one in 500 people, and can cause cardiac arrest and sudden death.
But research funded by the British Heart Foundation found current guidelines for diagnosing the condition were wholly inadequate. The findings were published in the Journal of the American College of Cardiology.
Two in three people diagnosed with HCM are men, but researchers said women were just as likely to have the condition.
HCM is diagnosed using a variety of tests and scans, such as measuring the thickness of the wall of the left ventricle, the heart’s main pumping chamber.
For the past five decades, the threshold for diagnosing HCM has been 15mm for everyone. If the muscle is thicker than this, the patient is considered likely to have HCM.
Research found this was inadequate and did not account for natural differences in sex and body size. The study included 1,600 patients with HCM whose condition was examined using a new method, taking account of age, sex and size.
Researchers found that the new method, which included AI reading thousands of heart scans, was particularly beneficial for women, increasing identification of HCM by 20 percentage points.
Further testing was carried out on data from more than 43,000 people on the UK Biobank. When the new personalised thresholds were applied, the overall number of people identified with HCM was lower, suggesting fewer misdiagnoses.
There was also a more even split between men and women, with women making up 44% of those identified, reflecting the belief that women have been missing out on diagnosis.
Dr Hunain Shiwani, a clinical research fellow at University College London and St Bartholomew’s hospital, who led the research, said the current threshold was based on studies from the 1970s and needed to be reconsidered.
He said: “Having the same cut-off for everyone regardless of age, sex or size completely ignores the fact that heart wall thickness is strongly influenced by these factors.
“Our research provides a long-overdue update showing that a personalised approach improves the accuracy of diagnosis.
“Effective treatments for HCM are starting to be used for the first time, making it more important than ever that we can correctly identify those who need them.”
Dr Sonya Babu-Narayan, a clinical director at the British Heart Foundation and a clinical cardiologist, said: “Hypertrophic cardiomyopathy is a severe, potentially life-threatening condition, and missed diagnosis means people that might benefit from new and effective treatments could slip through the net.
“At the same time, a diagnosis is itself a life-changing event and we should be making every effort to prevent misdiagnosing people.
“By updating the traditional one-size-fits-all approach, this study redefines abnormal heart wall thickness, a key contributor to the diagnosis of hypertrophic cardiomyopathy.
“As a result, more women and small individuals were identified who would otherwise be underdiagnosed.”
