Almost half of patients hospitalized for acute heart failure in Europe are readmitted within a year, according to a new study led by researchers at Karolinska Institutet and published in the European Heart Journal. The risk of death also remains high, especially for those with more severely reduced heart function.

Heart failure is a common condition affecting over 64 million people worldwide. The new study, conducted by an international team and coordinated by Karolinska Institutet in Sweden, analyzed data from more than 10,000 patients across 41 countries between 2018 and 2020. Patients were divided into two groups: those admitted for acute heart failure and those attending planned outpatient visits for chronic heart failure.

The study is unique because it tracked both mortality and hospital readmissions, as well as the different specific causes of death and hospitalization. We also conducted a detailed analysis of the heart’s pumping ability, known as ejection fraction, which can either be reduced, mildly reduced, or preserved.”


Lars Lund, study’s main author, professor of cardiology at the Department of Medicine, Solna, Karolinska Institutet and senior consultant at the Cardiology Department of Karolinska University Hospital

The findings show that 5.1 per cent of patients with acute heart failure died during their hospital stay. Among those who survived, the risk of death over the following year varied greatly depending on heart function. Patients with reduced ejection fraction faced the highest risk. 44 per cent of patients with acute heart failure and reduced ejection fraction were readmitted at least once during the year after their initial hospitalization. In contrast, only 18 per cent of patients with preserved ejection fraction treated as outpatients were readmitted.

“Patients with acute heart failure have approximately twice the risk of readmission and three times the risk of death compared to those treated as outpatients,” says Lars Lund.

“This kind of detailed data is important for planning healthcare and designing future clinical studies,” he continues.

The research highlights the need for careful follow-up and tailored care for heart failure patients, especially those with acute symptoms and reduced heart function.

The study was part of the European Society of Cardiology’s research programme and was funded by several pharmaceutical companies.

Source:

Journal reference:

Lund, L. H., et al. (2026) Outcomes of heart failure with reduced, mildly reduced, or preserved ejection fraction: the ESC HF III registry. European Heart Journal. DOI: 10.1093/eurheartj/ehaf1074. https://academic.oup.com/eurheartj/advance-article/doi/10.1093/eurheartj/ehaf1074/8494560