44% of Hospitalized Heart Failure Patients Are Readmitted Within a Year

Nearly half of patients hospitalized in Europe for acute heart failure do not complete the following year without returning to the hospital. One in twenty dies before leaving after their initial admission. And those managed for the condition as outpatients face a fundamentally different prognosis than those admitted acutely - with roughly triple the one-year mortality risk for the acute group.

Those are the headline figures from a study coordinated by Karolinska Institutet in Sweden and published in the European Heart Journal. The analysis tracked outcomes for more than 10,000 heart failure patients across 41 countries between 2018 and 2020.

How much the heart is pumping matters enormously

The study divided patients by ejection fraction - the proportion of blood the heart pumps out with each beat. Ejection fraction can be reduced, mildly reduced, or preserved, and the distinction has major implications for prognosis.

Among patients hospitalized for acute heart failure with reduced ejection fraction, 44% were readmitted at least once during the year following their initial discharge. For patients with preserved ejection fraction managed as outpatients, that figure fell to 18%. The gap in mortality was similar in direction but larger in magnitude: acute patients faced approximately twice the readmission risk and three times the death risk compared to outpatient-managed cases.

In-hospital mortality overall stood at 5.1% for the acute heart failure group - a figure that reflects the severity of acute presentations but also represents a substantial absolute burden given that heart failure affects more than 64 million people worldwide.

"The study is unique because it tracked both mortality and hospital readmissions, as well as the different specific causes of death and hospitalisation," said Lars Lund, professor of cardiology at Karolinska Institutet and the study's main author. "We also conducted a detailed analysis of the heart's pumping ability, which can either be reduced, mildly reduced, or preserved."

Planning for the full year, not just the admission

The findings have direct implications for how post-discharge care is structured. If 44% of the highest-risk patients return to hospital within a year, the period between discharge and potential readmission represents a critical window for intervention. Current standard care varies substantially across European health systems in how intensively it monitors recently discharged heart failure patients.

"This kind of detailed data is important for planning healthcare and designing future clinical studies," Lund said. The cross-national scope makes it possible to identify whether readmission rates differ between health systems.

The study was part of the European Society of Cardiology's research programme and was funded partly by pharmaceutical companies. The authors reported no conflicts of interest related to the study design or findings.

The recruitment period of 2018 to 2020 predates broader adoption of SGLT2 inhibitors, a drug class showing meaningful mortality and hospitalization benefits in heart failure. How the landscape may have shifted with more widespread use of these agents would not be captured in this dataset.