A late-breaking scientific presentation at the recently concluded Heart Failure 2023, a scientific conference of the European Society of Cardiology (ESC) in Prague, revealed that heart failure is frequently misdiagnosed, especially among women depriving patients of therapies that can increase well-being and lower mortality.

Commenting on the study’s findings, the principal investigator Professor John Cleland of the University of Glasgow, said, “For patients with heart failure, lifestyle advice, medicines and devices can improve symptoms, reduce morbidity and prolong life, but this requires someone to recognise and diagnose the condition.”

Pointing out that earlier diagnosis helps in more effective treatment, he added, “However, the results of this analysis suggest that most patients with heart failure die without the diagnosis ever being recognised.”

Before a diagnosis of heart failure becomes known, which generally occurs only after breathing difficulties and ankle oedema become severe enough to require hospitalisation, many people with the condition exhibit symptoms and signs for years.

According to ESC Guidelines loop diuretics,  a class of medicines, used to treat hypertension and oedema often caused due to congestive heart failure or chronic kidney disease to treat symptoms and signs of congestion due to heart failure are recommended and therefore loop diuretics might be considered an indication for symptoms and signs of heart failure requiring further investigation.

Elaborating about their study, Professor Cleland said,  “My colleagues and I noticed that many patients without a diagnosis of heart failure were treated with loop diuretics in an international trial of atrial fibrillation.”

“Prognosis was more strongly related to the use of loop diuretics than to a diagnosis of heart failure,” he added.

Pointing out that the research team subsequently showed similar results in an international trial of type 2 diabetes, he further added, “We suspected that many patients taking loop diuretics had heart failure, but it had just not been recognised.”

Using electronic health records for around one million adults in the Greater Glasgow and Clyde area of Scotland, the researchers investigated the relationship between a diagnosis of heart failure, loop diuretic dispensing and prognosis.

In 2010-11, the researchers found that 13,000 adults (1.3%) had a diagnosis of heart failure, which was similar to the UK average in terms of prevalence, but 31,807 (3.2%) people were receiving loop diuretics.

About a quarter or 7,844 patients getting loop diuretics, according to the researchers, had received a heart failure diagnosis.

They also found that patients taking loop diuretics were of similar age whether or not they had a heart failure diagnosis.

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Interestingly, 70% of those taking loop diuretics without a diagnosis of heart failure were women whereas only 50% of those who also had a diagnosis of heart failure were women.

Tracking the patients who were neither taking loop diuretics nor had a diagnosis of heart failure over the next five years, the researchers found that those taking loop diuretics were three times more (9%) than were diagnosed with heart failure (3%).

Noting that a few patients have been put on loop diuretics, mainly by primary care physicians, were investigated for heart failure by echocardiography or by measuring natriuretic peptides although many had blood samples taken for other tests such as haemoglobin or creatinine.

The researchers found that the people taking loop diuretics at baseline were more likely to be diagnosed with heart failure in the following five years (11%) than people not taking loop diuretics at baseline (3%).

The researchers noted that by five years, approximately 18% of those included in the cohort had died, with 23% diagnosed with heart failure (86% also treated with loop diuretics) and 32% preceded by the initiation of loop diuretics but without a diagnosis of heart failure, and that of patients given loop diuretics without a diagnosis of heart failure at baseline, 40% died during follow-up but only 11% received a new diagnosis of heart failure.

The researchers found that only 25% of individuals receiving loop diuretics (7,844 patients) experienced heart failure.

“While some patients taking loop diuretics were eventually told they had heart failure, many more died without ever receiving a diagnosis and therefore the opportunity for treatments to improve their outcome,” Professor Cleland said.

“It is likely that many patients treated with loop diuretics have undiagnosed heart failure. It is also possible that the inappropriate use of loop diuretics is driving adverse outcomes. Any patient treated with loop diuretics should be investigated for serious underlying heart disease, either by measuring natriuretic peptides or doing an echocardiogram or both. The combination of undiagnosed heart failure and inappropriate loop diuretic use may be one of the largest and most serious problems that cardiologists have yet to tackle. Ignoring it and hoping it goes away would be a tragedy,” he concluded.