Table 2.

Pooled OR estimates of specific risk factors (%) and associated 95% CI

Risk factor	Studies (n)	Category	Subjects (n)	Number with 30-day hospital readmission	Pooled OR (95% CI)
Demographics
Gender	16	Female	1 131 305	148 167	0.94 (0.91 to 0.97)
		Male	1 032 472	156 109
Age	8	≥65	887 353	122 710	1.23 (1.08 to 1.40)
		<65	608 471	78 647
Race	14	White	1 452 006	198 337	0.89 (0.84 to 0.94)
		Non-White	663 475	99 747
Insurance type	7	Medicare and Medicaid	589 376	97 976	1.41 (1.22 to 1.63)
		Private insurance	221 078	29 042
Comorbidities
Heart failure	4	Yes	9173	2052	1.81 (1.67 to 1.96)
		No	33 283	4941
Respiratory disease	8	Yes	135 281	24 203	1.33 (1.31 to 1.36)
		No	468 257	66 317
Depression	6	Yes	62 871	10 524	1.32 (1.20 to 1.45)
		No	441 233	51 700
Renal disease	4	Yes	84 595	16 671	1.69 (1.34 to 2.12)
		No	330 966	44 477
Hypertension	6	Yes	194 365	30 292	1.01 (0.98 to 1.03)
		No	114 349	15 172
Diabetes-related medication
Insulin therapy	5	Yes	272 420	38 440	1.45 (1.24 to 1.71)
		No	637 554	70 684
Inpatient factor
Length of stay (days)	3		1 996 909		1.06 (1.01 to 1.12)