Table 2.

Interrupted Time Series Regression Model for the Primary Outcomes at the Intervention South Side Chicago Hospital and Comparison to North Side Chicago Hospitals and St Louis Hospitals

	Intervention Hospital		Comparison With North Side Chicago Hospitals		Comparison With St Louis Hospitals
	β	95% CI	β	95% CI	β	95% CI
Early arrival (<3 h from symptom onset)
Intercept	0.287	0.227, 0.348	−0.152	−0.231, −0.072	0.032	−0.030, 0.094
Time	−0.002	−0.005, 0.001	0.005	−0.001, 0.009	−0.003	−0.006, 0.0001
Level change	−0.001	−0.106, 0.103	−0.043	−0.181, 0.094	0.035	−0.072, 0.142
Slope change	0.005	−0.002, 0.012	−0.003	−0.012, 0.006	0.007	−0.001, 0.014
EMS arrival
Intercept	0.587	0.513, 0.661	0.028	−0.055, 0.111	0.013	−0.062, 0.088
Time	−0.001	−0.004, 0.004	0.003	−0.001, 0.007	−0.0002	−0.004, 0.004
Level change	0.056	−0.100, 0.211	−0.092	−0.267, 0.083	0.043	−0.116, 0.202
Slope change	−0.008	−0.017, 0.002	<0.001	−0.011, 0.011	−0.007	−0.017, 0.003

A level change is an abrupt change right after intervention implementation. A slope change is the change per month over time after intervention implementation. EMS indicates emergency medical services.