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Hospitals Participating in the Medicare Shared Savings Program Show Reduced Readmissions for Stroke Patients, but Disparities Persisted between Safety-Net and Other Hospitals
Accountable Care Organizations (ACOs) participating in the Medicare Shared Savings Program (MSSP) are responsible for the quality and the cost of care of Medicare Fee-for-Service beneficiaries attributed to them. The MSSP is intended to improve patient outcomes and reduce costs through improved coordination of care. The primary goal of this study was to assess the impact of MSSP on hospital readmissions and mortality in Medicare patients initially admitted for stroke. We also examined whether the MSSP was associated with changing disparities in readmission and mortality rates between safety-net hospitals (SNHs) and non-SNHs.
Research Design
We obtained Hospital Compare data on risk-standardized 30-day readmission and 30-day mortality rates for Medicare patients originally admitted for stroke between 2010 and 2017. We used propensity score method to match every MSSP-participating hospital to 3 non-participating hospitals (1:3 matching). Hospital-level difference-in-difference (DID) analysis was used to compare changes in hospital readmission and mortality rates over time for MSSP-participating hospitals relative to non-participating hospitals. We also conducted hospital-level DID analysis to examine whether participation in the MSSP had differential impacts on SNHs versus non-SNHs.
Subjects
Urban acute care hospitals that participated in the MSSP during the 2012-2015 period and that did not participate in any of the other Medicare ACO programs (For stroke readmission rate: n =1,624; for stroke mortality rate: n=1,636).
Results
During 2010-17, hospital readmission rates among Medicare stroke patients decreased by 1.28 percentage points. MSSP-participating hospitals had greater reductions in readmission rates than matched non-participating hospitals (by 0.23 percentage points; 95% CI: -0.40, -0.06, p-value 0.008). Mortality rates after initial admission for stroke reduced among all hospitals but mortality reduction was not significantly different between MSSP-participating hospitals and matched hospitals.
Prior to MSSP, readmission rates in SNHs were higher compared to non-SNHs. The MSSP had a significant effect of readmission reductions for both SNHs and non-SNHs. However, the MSSP effect on readmission (mortality) was not statistically significantly different for SNHs compared to non-SNHs.
Conclusions
Hospital participation in the MSSP led to fewer readmissions in Medicare patients initially hospitalized for stroke. However, the MSSP is associated with similar readmission reductions in SNHs and non-SNHs, and thus disparities persisted over time.