Relation of a Simple Cardiac Comorbidity Count and Cardiovascular Readmission After a Heart Failure Hospitalization

ABSTRACT While several risk calculators are available to determine risk for readmission following a heart failure (HF) hospitalization, none provide information on cause-specific readmission. Understanding risk for cause-specific readmission could aid in developing a targeted approach to reducing readmissions. We sought to determine if a simple cardiac comorbidity count could identify individuals at high risk for a cardiovascular readmission following a HF hospitalization. Using the Nationwide Readmissions Database, we examined non-fatal hospital discharges with a principal diagnosis of HF. We calculated a 0-3 cardiac comorbidity count based on the presence of coronary artery disease (CAD), atrial arrhythmia, and/or ventricular arrhythmia. We used a multinomial logistic regression to determine if the cardiac comorbidity count was independently associated with cardiovascular (CV) readmission or non-CV readmission, adjusting for patient- and hospital-level confounders. Among 380,075 discharges, 28% had a comorbidity count of 0, 47% had a count of 1, 23% had a count of 2, and 2% had a count of 3. In a fully-adjusted model, cardiac comorbidity count was independently associated with CV readmission: compared to individuals with a count of 0, the relative risk for those with a count of 1 was 1.27 (95% CI:1.23-1.31); for those with a count of 2 was 1.40 (95% CI:1.35-1.46); and for those with a count of 3 was 1.36 (95% CI:1.23-1.51). Cardiac comorbidity count was not independently associated with non-CV readmission. In conclusion, we found that a simple cardiac comorbidity count was independently associated with increased risk of CV but not non-CV readmission.