Table 3.

Outcomes of unplanned hospital readmissions to a different hospital: findings of causal inferences^a

Different-hospital readmission (Yes = 1)b
	û1	û0	DR estimate	CI	P-value
In-hospital deaths	0.081	0.067	0.015	0.0089 to 0.021	<0.001
Adverse events	0.0056	0.0063	−0.0007	−0.0076 to 0.0062	0.84
Second readmission	0.206	0.213	−0.0063	−0.015 to 0.0024	0.16
Cost ($)	15 671.8	14 286.4	1385.4	988.1 to 1782.6	<0.001
Length of stay	6.495	6.436	0.058	−0.112 to 0.229	0.50

^aThe reference group includes patients rehospitalized to the index hospital; all the patient, hospital and county characteristics in Table 1 and 17 dummies for 18 clinical condition groups [17] were included in the propensity model; and the details of the analytic approach for the causal inference are in Supplementary Appendix 1.

^bû₁ (û₀) is the estimated mean assuming all were readmitted to a different (the same) hospital. The DR estimate is û₁– û₀.