Abstract Body (Do not enter title and authors here): Introduction: Radiation therapy (RT) is an important part of treatment strategies in cancer patients, but it carries multiple significant cardiovascular risks. Data regarding the effects of RT in heart failure patients is limited. In our study, we investigated the readmission rates, predictors, and causes of readmission in heart failure patients with a history of RT.

Methods: The National Readmission Database for 2018 and 2020 was queried to identify hospitalized adults with Congestive heart failure (CHF) and a history of RT. Multivariate logistic and linear regression analyses were used to adjust for possible confounders.

Results: A total of 2,607 patients were hospitalized for acute exacerbation of congestive heart failure and had a history of RT with 2,497 discharged alive. Within 90 days from discharge, 874 (35%) were readmitted. Exacerbation of CHF with a history of CKD or hypertension (27%), Sepsis (6.6%), Pneumonia (3.1%), and acute kidney injury (2.3%) were the most common causes of readmissions. Independent predictors of readmission included presence of anemia (aOR 1.46, 95% CI: 1.1 - 1.92, P=0.007), discharge against medical advice (aOR 2.9, 95% CI: 1.07-7.97, P=0.03), and presence of atrial flutter/Fibrillation (aOR 1.36, 95% CI: 1.03-1.81, P=0.03).

Conclusion: Predictors of readmission included discharge against medical advice, anemia, and atrial flutter/ Fibrillation. The most common causes of readmission included Exacerbation of CHF, Sepsis, Pneumonia, and acute kidney injury. Addressing readmission causes and predictors is needed to prevent such a high rate of readmission.