Readmissions performance and penalty experience of safety-net hospitals under Medicare’s Hospital Readmissions Reduction Program

Table 2 Difference in 30-day risk adjusted readmission rates between safety-net and non-safety-net hospitals, 2009-2010 and 2014-2016

	30-day risk adjusted readmission rate (%)
	Safety-net hospitals	Non-safety-net hospitals
A. Acute myocardial infarction
Pre-period	20.3	19.8
Post-period	17.6	17.2
Pre to Post Difference	−2.7***	− 2.6***
Difference-in-differences	− 0.08
B. Heart failure
Pre-period	25.3	24.3
Post-period	22.9	22.1
Pre to Post Difference	−2.4***	−2.3***
Difference-in-differences	−0.14
C. Pneumonia
Pre-period	18.8	18.2
Post-period	17.5	17.2
Pre to Post Difference	−1.3***	−1.1***
Difference-in-differences	−0.23***

1) Safety-net hospitals: hospitals that fall in the top quartile of the Disproportionate Share Hospital (DSH) index; non-safety-net hospitals: hospitals in the bottom three quartiles of the DSH index
2) Pre-period denotes the year 2009-2010; post-period denotes the period 2014-2016
3) The sample sizes for the AMI, heart failure, and pneumonia cohorts are 7225; 9370 and 7580 hospital-years, respectively
4) Observed average readmission rates reported for pre-period and post-period. Difference in average readmission rate between post vs. pre period reported for safety-net and non-safety-net hospitals based on linear random effects model regressing mortality rate on post-period indicator; heteroscedasticity-robust standard errors clustered at the hospital level
5) Difference-in-differences estimates from random effects model reported; heteroscedasticity-robust standard errors clustered at the hospital level; covariates in the model include teaching hospital status, ownership, bed size, year and region. Full model estimates are reported in Additional file 1: Table 3. Note that Medicaid and Medicare share of aggregate inpatient days (Table 1) are not included as covariates since they are likely to be associated with the categorization of hospitals into safety-net and non-safety-net hospitals
6) *** p < 0.01

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