Almost half of patients admitted to hospital 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. In addition, the risk of death remains high, especially for those with more severe heart failure.

Heart failure is a common condition that affects over 64 million people worldwide. The new study, conducted by an international team, analyzed data from over 10,000 patients in 41 countries between 2018 and 2020. The patients were divided into two groups: those admitted for acute heart failure and those who presented for scheduled visits for chronic heart failure.

– The study is unique because it followed both mortality and readmissions to hospital, as well as the different specific causes of death and hospitalisation. In addition, a careful analysis was made of the heart’s pumping ability, so-called ejection fraction, which can be impaired, moderately impaired or maintained, says the study’s lead author Lars Lund , professor of cardiology at the Department of Medicine, Solna , Karolinska Institutet and senior consultant at the Heart Clinic at Karolinska University Hospital.

The results show that 5.1 percent of patients with acute heart failure died during their hospital stay. Among those who survived, the risk of dying in the following year varied greatly depending on heart function. Patients with reduced ejection fraction were at greatest risk.

Greatly increased risk of death

44 percent of patients with acute heart failure and reduced ejection fraction were readmitted at least once during the year after their initial hospital admission. The corresponding figure for patients with preserved ejection fraction who were treated without needing to be admitted to hospital, i.e. in outpatient care, was only 18 percent.

– Patients with acute heart failure have approximately twice the risk of readmission and a threefold increased risk of death compared to those treated in outpatient care, says Lars Lund.

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

The researchers emphasize the need for careful follow-up and individualized care for patients with heart failure, especially for those with acute symptoms and impaired heart function.

The study was part of the European Society of Cardiology’s research program and was funded by several pharmaceutical companies. The authors report no conflicts of interest related to the study.

Publication

“Outcomes of heart failure with reduced, mildly reduced, or preserved ejection fraction: the ESC HF III registry” , Lars H. Lund, Aldo P Maggioni, Maria G Crespo-Leiro, Cecile Laroche, Israel Gotsman, Belma Pojskic, Eleonora B. Vataman, Lucica Grigorica, Hamayak Sisakian, Duska Glavas, Dulce A. Brito, Stefan Anker, Ovidiu Chioncel, Gerasimos Filippatos, Mitja Lainscak, Theresa A. McDonagh, Alexandre Mebazaa, Massimo Piepoli, Frank Ruschitzka, Gianluigi Savarese, Petar M. Seferović, Marco Metra, Giuseppe Rosano,  European Heart Journal , online 25 February 2026, doi: 10.1093/eurheartj/ehaf1074.