Most hospital readmissions after heart failure are not heart-related

By Dr. Priyom Bose, Ph.D.Reviewed by Lauren HardakerJul 8 2026

Non-cardiovascular conditions account for most hospital readmissions after heart failure, and new research suggests that taking multiple non-heart medications may identify patients at greatest risk.

Study: Predictors of Non-Cardiovascular Readmissions in Multimorbid Adults with Heart Failure in Australian Hospitals: A Retrospective Cohort Study. Image credit: PeopleImages/Shutterstock.com

Adults with heart failure who take multiple non-cardiovascular medications may face a greater risk of returning to the hospital for non-heart-related conditions, according to a recent study published in the Journal of Clinical Medicine.

Non-heart conditions drive most heart failure readmissions

Heart failure is a complex clinical syndrome in which the heart cannot pump enough blood to meet the body’s metabolic demands. This condition carries significant global and national health implications, impacting 64 million people worldwide and a considerable number in Australia.

Despite therapeutic advancements, hospital readmissions are common, with two-thirds attributed to non-cardiovascular causes and many deemed preventable. Most interventions have focused on cardiovascular-specific factors, resulting in a limited understanding of non-cardiovascular readmissions. This highlights a critical research gap in identifying the determinants and risk factors underlying these events.

While guideline-directed therapies have effectively reduced heart failure-related hospitalizations, non-cardiovascular admissions remain more prevalent and less well understood. Medication-related harms, such as adverse drug reactions, injurious falls, and drug-disease interactions, are frequent contributors to preventable hospitalizations in older, multimorbid individuals.

The relationship between the use of potentially inappropriate non-cardiovascular medications and subsequent readmissions remains poorly defined, reflecting a key gap in current knowledge. Addressing this gap by identifying modifiable medication-related risk factors is essential to inform strategies that reduce preventable non-cardiovascular hospitalizations.

Australian hospitals tracked readmissions over one year

The current retrospective cohort study used hospital admission data from four major hospitals in Adelaide, South Australia, between August 2016 and June 2022, with follow-up to June 2023. The study included approximately 198,000 annual inpatient admissions.

Adults aged 45 years and older with heart failure and multimorbidity admitted for the first time during the study period were included. Only patients whose heart failure was actively managed and documented during admission were considered.

Eligible admissions were unplanned, acute, managed in general comorbidity units, and required an inpatient stay of at least 48 hours. Patients who did not survive or were transferred were excluded. Study variables included age, gender, International Classification of Diseases (ICD-10) codes, and regular discharge medications from the electronic medical record (EMR). The Charlson comorbidity index (excluding heart failure) and medication classes were determined using ICD-10 and Anatomical Therapeutic Chemical (ATC) codes.

The current study defined non-cardiovascular polypharmacy as the use of five or more unique non-cardiovascular medications. This was hypothesized to increase risk for all-cause and non-cardiovascular readmissions due to medication-related harm. Acute hospital readmissions were tracked for one year post-discharge at three-month intervals.

Non-cardiovascular readmissions exceeded cardiac hospitalizations

This study followed 4,912 adults with heart failure and multiple chronic conditions who were discharged to home or residential care. The cohort was elderly, with a median age of 82 years, and nearly half of the participants were women. Patients typically had six additional chronic conditions alongside heart failure, and more than half were classified as frail, highlighting the complex health needs of the study population.

Patients were prescribed a median of 10 medications, split almost equally between cardiovascular and non-cardiovascular treatments, and 56% met the definition of non-cardiovascular polypharmacy by taking five or more non-cardiovascular medicines.

Over the year following discharge, non-cardiovascular hospitalizations were more common than cardiovascular ones. By 12 months, 32% of patients had experienced at least one non-cardiovascular readmission, compared with 19% who were readmitted for cardiovascular reasons, while 28% had died. Many patients experienced multiple hospitalizations during follow-up.

The burden of chronic illness was substantial, with high blood pressure, high cholesterol, acid reflux, ischemic heart disease, diabetes, chronic lung disease, and depression among the most common comorbidities. As follow-up progressed, the cumulative incidence of first all-cause readmission approached 37% by 12 months, while the corresponding cumulative incidence of death reached 15%.

Patients taking five or more non-cardiovascular medications experienced poorer outcomes overall. Their cumulative incidence of all-cause readmission reached 39% at 12 months, compared with 32% among those without non-cardiovascular polypharmacy, while the cumulative incidence of death was also higher (17% versus 10%).

Regression analyses further showed that non-cardiovascular polypharmacy was independently associated with a 48% increase in the odds of non-cardiovascular readmission within one year. The likelihood of readmission also increased with each additional cardiovascular condition, whereas age and sex were not independently associated with non-cardiovascular readmission. In contrast, adults aged 75 years and older were more likely to experience all-cause readmission during follow-up.

Addressing the overlooked risks of polypharmacy

The current study reveals that older adults with heart failure who take multiple non-cardiac medications had higher rates of non-cardiovascular readmission and mortality. These findings suggest that non-cardiac polypharmacy may contribute to harm or reflect a greater burden of illness.

Optimizing medication regimens and addressing comorbidities could reduce unnecessary hospitalizations. A holistic, patient-centered approach to medication management is needed to improve outcomes for multimorbid adults living with heart failure.

However, because this was a retrospective observational study, the findings cannot establish that non-cardiovascular polypharmacy directly causes readmissions. The authors also note that the results may not be generalizable to specialist hospital units, regional or private hospitals, community-dwelling adults, or healthcare systems outside Australia.

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