Background: Although readmission rates have decreased since the implementation of higher-than-expected 30-day readmission penalties by the Centers for Medicare & Medicaid Services (CMS), rates remain above optimal. Hospital readmissions reflect two processes: discharge planning and access to care after discharge. To increase access to care, the US Congress passed the Patient Protection and Affordable Care Act in 2010, which included Medicaid expansion. However, not all States allowed Medicaid expansion resulting in variable insurance coverage. Thus, the US states that expanded Medicaid and thereby increased access to care may have larger readmission reductions than states that did not. To test this hypothesis, we examined hospital readmissions since 2005 to determine if the readmission reduction trends of hospitals differ by the Medicaid expansion status of the states in which these hospitals were located.

Methods: We obtained data from four sources: 1) hospital characteristics and readmissions data from CMS, 2) regional demographic and economic data from the US Census Bureau, 3) hospital catchment area data from the Dartmouth Atlas of Healthcare, and 4) state Medicaid expansion data from the Kaiser Family Foundation. We divided states into those that expanded Medicaid in 2014 and those that had not expanded until 2020; five states that expanded Medicaid between 2014 and 2020 were excluded. We examined the relationship between Medicaid expansion and 30-day readmissions after hospitalizations for pneumonia, heart failure (HF), and acute myocardial infarction (AMI) in a difference-in-difference framework. Adjusted models included the following potential confounding variables: hospital ownership, teaching status of the hospital, number of hospital beds, number of nurses, rural vs. urban location of the hospital, and hospital catchment area population characteristics (total population, median income, poverty percentage, African American percentage, and percentage with insurance).

Results: Of the 3,015 hospitals, 52% (1,451) were in states with Medicaid expansion. States without Medicaid expansion (N=19) had more for-profit hospitals (26% vs. 12%; P< 0.001), hospitals in rural areas (38% vs. 21%; P< 0.001), and non-teaching hospitals (79% vs. 61%; P< 0.001). Before 2014, 30-day readmission rates were higher in hospitals located in the Medicaid-expansion states than those in non-Medicaid-expansion states (pneumonia = 18.2% vs. 17.9%; HF = 24% vs. 23.7%; AMI = 19.1% vs. 18.8%; all P< 0.001). Across all hospitals in the US, readmissions were significantly lower after 2014 than before 2014 for pneumonia (-1.2%, 95%CI = -1.2%, -1.1%; P< 0.001), HF (-2.0%, 95%CI = -2.1%, -1.9%; P< 0.001), and AMI (-3.0%, 95%CI = -3.1%, -2.9%; P< 0.001). The drop in readmission reductions before and after 2014 was larger for hospitals in the Medicaid-expansion states than those in the non-Medicaid-expansion States; difference-in-difference for pneumonia (-0.13%; 95%CI = -0.23%, -0.04%; P=0.006), HF (-0.23; 95%CI = -0.35%, -0.11%; P< 0.001), AMI (-0.19%; 95%CI = -0.28, -0.10; P< 0.001). These results remained significant after adjusting for potential confounders.

Conclusions: Hospitals located in states that expanded Medicaid had larger reductions in 30-day hospital readmission than hospitals located in states that did not expand Medicaid. Better access to healthcare may be responsible for the observed difference.

IMAGE 1: 30-Day Readmissions for Pneumonia, Heart Failure, and Acute Myocardial Infarction