Table 4. Effect of certified hospital admission on mortality by instrument variable method, adjusting for hospital characteristics and treatment processes.

	Model 1a		Model 2b		Model 3c
	Coefficient	95% CI	Coefficient	95% CI	Coefficient	95% CI
7-day in-hospital mortality	−0.370***	[−0.643, −0.097]	−0.429***	[−0.710, −0.148]	−0.430***	[−0.723, −0.136]
14-day in-hospital mortality	−0.266**	[−0.500, −0.033]	−0.279***	[−0.517, −0.040]	−0.259**	[−0.505, −0.013]

CI, confidence interval.

^aModel 1, adjusted for age, sex, and functional deficit on admission.

^bModel 2, adjusted for age, sex, functional deficit on admission, and all hospital structural factors (hospital size, hospital volume, doctor-to-patients ratio, nurse-to-patients ratio).

^cModel 3, adjusted for age, sex, functional deficit on admission, and use of treatment processes (thrombin inhibitor argatroban within 2 days, aspirin within 2 days, ozagrel sodium within 5 days, and glycerol during the hospitalization).

*P < 0.1, **P < 0.05, ***P < 0.01.