Heart failure is frequently misdiagnosed, depriving patients of therapies that could improve their health and reduce their death. According to a late-breaking scientific presentation today at Heart Failure 2023, a scientific congress of the European Society of Cardiology (ESC), most individuals with heart failure die without ever being diagnosed.
“For patients with heart failure, lifestyle advice, medicines, and devices can improve symptoms, reduce morbidity and prolong life, but this requires someone to recognize and diagnose the condition.” said principal investigator Professor John Cleland of the University of Glasgow, UK.
Many patients with heart failure experience symptoms and signs for years before being diagnosed, usually only after the dyspnoea and ankle edema become severe enough to necessitate hospitalization.
The ESC Guidelines recommend loop diuretics to treat symptoms and indications of congestion caused by heart failure. As a result, loop diuretics may be used as a substitute for heart failure symptoms and indicators requiring additional examination.
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.4 Prognosis was more strongly related to using loop diuretics than diagnosing heart failure. We subsequently showed similar results in an international trial of type 2 diabetes.5 We suspected that many patients taking loop diuretics had heart failure, but it had just not been recognized.”
The researchers examined the link between a diagnosis of heart failure, loop diuretic dispensing, and prognosis using electronic health records from around one million persons in the Greater Glasgow and Clyde area of Scotland. At the start of the study (2010/11), 13,000 persons (1.3%) were diagnosed with heart failure, but 31,807 (3.2%) were taking loop diuretics. Only one-quarter (7,844 patients; 25%) of those using loop diuretics had been diagnosed with heart failure.
Patients on loop diuretics were similar in age, whether they had a heart failure diagnosis or not. However, 70% of those taking loop diuretics without a diagnosis were women, whereas only 50% of those with a heart failure diagnosis were women.
Between 2010 and 2011, 198,898 people were treated for various cardiovascular illnesses. Loop diuretics alone (23,963 patients; 12%), heart failure diagnosis alone (5,156; 3%), both (7,844; 4%), or neither (161,935 patients; 81%).
Over the next five years, those who were neither taking loop diuretics nor had a diagnosis of heart failure (Group 4) began taking loop diuretics three times more (9%) than those who were diagnosed with heart failure (3%).
Few patients started on loop diuretics were evaluated for heart failure using echocardiography or natriuretic peptide measurements, while many had blood samples drawn for another testing, such as haemoglobin or creatinine.
People who took loop diuretics at the start were 11% more likely to be diagnosed with heart failure in the next five years than people who did not take loop diuretics at the start (3%). By five years, about 35,000 (18%) people in the cohort had died; a diagnosis of heart failure preceded 23% of these deaths.
Professor Cleland said: “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 concluded: “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.