Predictors of Non-Cardiovascular Readmissions in Multimorbid Adults with Heart Failure in Australian Hospitals: A Retrospective Cohort Study

Background: Heart failure is common in hospitalised adults, who often have high rates of polypharmacy. Two-thirds of readmissions are for non-cardiovascular reasons, where medications and comorbidities are likely to be contributors. The aim of this study was to quantify the proportion of non-cardiovascular readmissions and examine the factors associated with non-cardiovascular readmissions among multimorbid adults with heart failure. Methods: We conducted a retrospective cohort study of multimorbid adults aged ≥ 45 years with heart failure who were discharged from four metropolitan hospitals between August 2016 and June 2023. Non-cardiovascular polypharmacy was defined as the use of five or more non-cardiovascular medications as extracted from the electronic medical record at discharge from the hospitals. Non-cardiovascular readmissions were defined as those with a non-cardiovascular condition as the principal diagnosis. The proportion of patients with one or more non-cardiovascular readmissions, cardiovascular readmissions, or deaths by 12 months was calculated. Logistic regression was used to determine the factors associated with the occurrence of a non-cardiovascular readmission over 12 months. Results: In total, 4912 patients were included in the study, with 56% (n = 2734) having non-cardiovascular polypharmacy. The proportion of patients with one or more non-cardiovascular readmissions was 32% at 12 months post-discharge. Nineteen percent of patients had one or more cardiovascular readmissions, while a further 28% had died by 12 months. Non-cardiovascular polypharmacy was associated with a 48% increase in the odds (OR 1.48 95% CI 1.28–1.72) of having a non-cardiovascular readmission within 12 months. Conclusions: Non-cardiovascular readmissions occurred more frequently than cardiovascular readmissions in adults with heart failure. Non-cardiovascular polypharmacy was associated with a 48% increase in the odds of having a non-cardiovascular readmission, potentially through medication-related harm or as a surrogate of comorbidity burden. Future studies should explore holistic approaches to the management of multimorbid adults with heart failure, including optimisation of comorbidities and non-cardiovascular medications.