Association between the number of hospital admissions and in-hospital outcomes in patients with heart failure

Readmission to the hospital is a major issue in clinical care for patients with heart failure (HF). However, the impact of the number of hospital admissions due to worsened HF is not fully understood. We sought to clarify the association between the number of hospital admissions due to worsened HF and patient outcomes. We studied 331,259 patients (median age was 81 years, and 175,286 patients (52.9%) were men) hospitalized for HF between January 2010 and March 2018 using the Japanese Diagnosis Procedure Combination Database, a national inpatient database. Patients were categorized into four groups based on the number of times they were admitted: once (n = 264,583), twice (n = 42,385), three times (n = 13,205), four times (n = 5347), and five or more times (n = 5739). The patients with larger numbers of admissions were more likely to have comorbidities and to use inotropic agents. The interval period between hospitalizations was shortened with an increasing number of hospital admissions, whereas the length of hospital stay was prolonged with an increasing number of hospital admissions. Multivariable logistic regression analysis fitted with a generalized estimating equation showed that an increased number of hospital admissions was independently associated with higher in-hospital mortality. In conclusion, readmission to the hospital due to worsened HF was still common, and in-hospital mortality was higher in those with larger numbers of readmissions, suggesting a clinical significance of the number of readmissions in patients with HF.