Abstract 10388: The Role of Patient, Community and Healthcare System Factors in the Variability of Cardiovascular Hospital Readmissions

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Introduction: The Hospital Readmissions Reduction Program (HRRP) penalizes hospitals by reducing Medicare (CMS) reimbursement for institutions with higher rates of readmissions following hospitalizations for myocardial infarction (MI), coronary artery bypass grafting (CABG) and heart failure (HF). Understanding the contributors to these readmissions can identify meaningful areas for intervention. We examine whether community and patient or healthcare system factors contribute more to variability in cardiac readmissions. Methods: We compiled CMS hospital data on MI, CABG and HF readmissions, CMS physician reimbursement data, and 2020-21 County Health Rankings (Credit: University of Wisconsin). The outcome was the ratio of a hospital’s composite readmissions for MI, CABG and HF to discharges for the same conditions. Physician/healthcare system factors included total cardiac subspecialists, presence of all subspecialties, and the mean proportion of reimbursed charges. Patient and community factors included mean Hierarchical Condition Category (HCC) risk score, median household income, proportion of residents reporting no physical activity, and access to food stores. Linear regression models were compared using R 2 , AIC, BIC in model training data and mean absolute prediction error (MAPE) and root mean square prediction error (RMSE) in test data. Results: The linear regression model incorporating community and patient factors explained greater variability in readmission rates in training data and performed with greater accuracy in the test data (R 2 0.35; AIC -1839; BIC -1811; MAPE 0.017; RMSE 0.022) than the model incorporating physician/healthcare system factors (R 2 0.04; AIC - 1685; BIC - 1664; MAPE 0.022; RMSE 0.027). HCC score, level of physical activity, and number of cardiac specialists were associated with the largest effect sizes on the outcome. Conclusions: At a county level, community and patient factors appear to contribute more to variability in hospitals’ MI, CABG and and HF readmission rates. Further analyses should explore other community, patient, and provider factors that may contribute. The HRRP does not account for community/patient factors, indicating its limitations.