Risk Factors Associated With 7-Versus 30-Day Readmission Among Patients With Heart Failure Using the Nationwide Readmission Database

Background: The 30-day all-cause readmission for heart failure (HF) is a standard measure to evaluate hospital performance. A recent study found that a shorter period after discharge may be more indicative of hospital quality. Objective: To compare risk factors for 7-versus 30-day readmission in patients with HF. Design: This is a retrospective cohort using the 2014 Nationwide Readmissions Database. Subjects: Patients 65 years and older with Medicare coverage discharged after HF admission. Measures: The 7- or 30-day all-cause readmissions were the outcomes of interest. HF-related readmissions were secondary outcomes. Covariates included patient characteristics, hospital characteristics, and admission-related information. Hierarchical logistic regression evaluated the association between covariates and readmissions. Results: There were N=15,039 all-cause readmissions within 7 days after discharge and N=47,896 within 30 days. Surgical service was a risk factor for 30-day but not 7-day all-cause readmission (odds ratio=1.10, 95% confidence interval=1.05-1.16). Depression, rheumatoid arthritis, liver disease, drug abuse, lymphoma, and psychosis were associated with an increased risk of 30-day all-cause readmission but not 7-day. Longer lengths of stay also had a higher likelihood of all-cause readmission within 30 days compared with 7 days. In contrast, smaller hospital bed size was associated with an increased risk of 7-day all-cause readmission (odds ratio=1.06, confidence interval=1.01-1.12) but not 30-day. Sensitivity analysis with using a 3-day readmission interval showed similar results. Conclusions: Risk factors for hospital readmission are slightly different dependent on the measurement interval. In general, hospital-related factors were associated with shorter readmissions intervals while patient factors were more associated with longer intervals.