The condition affects fewer than 1.5 per cent of adults, about half the number for Portugal, it was said. This is despite widespread beliefs that a classic Mediterranean diet high in olive oil and fish protects against the disease.

The findings are based on digital health records for 11 countries – Sweden, Norway, the UK, Belgium, Germany, Switzerland, Italy, Spain, Portugal, Israel and Canada.

Dr Anna Norhammar, of the Karolinska Institute in Stockholm, said: “The highest prevalence was in Portugal, just under three per cent. The lowest was in the UK, almost 1.5 per cent.

“The burden, risks and costs in patients highlights an urgent need for improved management – an area that policy-makers need to prioritise when planning healthcare for patients with heart failure.”

The Cardiorenal and Metabolic Disease Study, which appears in the journal Heart, is the biggest of its kind.

Dr Norhammar’s team summarised and pooled individual healthcare data for more than 600,000 people diagnosed with heart failure in the participating countries between 2018 and 2020.

The average age of patients was 75, with almost half women. The ­debilitating illness causes ­breathlessness, making even mundane chores tiring.

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It can also lead to swollen legs. Patients are at high risk of other serious complications and even death.

The costs, both human and fiscal, warrant immediate action, say scientists.

Heart failure will become more common as populations age and diagnosis improves, the researchers believe.

Some 170,000 study participants had their kidney function measured, with 49 per cent having moderate to severe chronic kidney disease.

Dr Norhammar added: “Risks of annual hospital admission were highest for those with heart failure and chronic kidney disease and lower for those with other cardiovascular disease, such as heart attack, stroke and peripheral artery disease.

“The annual death rate was 13 per cent.”