Anemia And Other Independent Predictors Of 30-day Readmissions In Heart Failure Patients: A Retrospective Study

Abstract

<h3>Objectives</h3> To determine if there is an association between anemia and 30-day readmissions in patients with heart failure, and to identify other risk factors for 30-day readmissions in this group. <h3>Background</h3> : Anemia commonly occurs in patients with chronic heart failure, with a prevalence of up to 79%. It can be explained by the presence of comorbidities, chronic kidney disease, and differences in heart failure treatment. Anemia is likely associated with worse clinical outcomes in those patients because of a mismatch in oxygen supply and demand, increased resistance to erythropoietin, higher rates of left ventricular hypertrophy and fluid overload, and chronic inflammation. Findings associated with anemia in heart failure patients include symptoms, echocardiogram measurements, renal function, mortality, hospitalization rates and lengths of hospital stays. Few studies, however, have assessed the association of anemia with 30-day readmission rates in these patients. <h3>Methods</h3> : We conducted a retrospective chart review of patients with heart failure admitted to Ascension St John Hospital in Michigan from 1/1/2018 to 12/31/2019. Data were collected on demographics, comorbidities, laboratory testing during the index hospitalization, echocardiogram findings, and 30-day readmissions. Anemia was defined as hemoglobin less than 13 g/dL in males and hemoglobin less than 12 g/dL in females. Data were analyzed using Student's t-test, the χ2 test and logistic regression. <h3>Results</h3> : We reviewed 1250 patients with heart failure, 58.2% male, 52.6% non-white, mean age 68.2 ± 15.3 years. Of those patients, 24.2% (303/1250) were readmitted within 30 days; 55.5% of those readmissions were a result of cardiovascular disease. Anemia was noted in 62.2% of the patients (778/1250). From univariable analysis, the following factors were found to be associated with 30-day readmissions in heart failure patients: anemia (p = 0.008), female sex (p = 0.03), pulmonary edema (p = 0.013), hyponatremia (p = 0.005), atrial fibrillation or flutter (p = 0.04), hyperlipidemia (p = 0.042), antiarrhythmic medications (p < 0.0001), and Charlson Weighted Index of Comorbidity (CWIC) score (p < 0.0001). From multivariable analysis, heart failure patients who were readmitted within 30 days were more likely to be anemic (OR = 1.4, p = 0.029), hyponatremic (OR = 1.5, p = 0.007), have pulmonary edema on chest imaging during the index hospitalization (OR = 1.4, p = 0.033), prescribed antiarrhythmic medications (OR = 1.8, p = 0.002), and have higher CWIC scores (OR = 1.1, p = 0.001). <h3>Conclusions</h3> : In patients with heart failure, after controlling for other risk factors, anemic patients were 40% more likely to be readmitted within 30-days compared to non-anemic patients. Other independent predictors of 30-day readmissions included hyponatremia, pulmonary edema, antiarrhythmic medications, and CWIC score.