Table 3.

Multivariate logistic regression model of CT utilization

	Odds ratio	95% CI
Patient Characteristics
Age, years
18–44 (ref)	-	-
45–64	1.43	0.93, 2.21
> 65	0.88	0.32, 2.38
Sex
Female (ref)
Male	1.83	1.22, 2.77
Race/ethnicity
Non Hispanic white (ref)	-	-
Non Hispanic black	0.67	0.38, 1.16
Hispanic	0.84	0.45, 1.58
Other	0.48	0.23, 0.98
Insurance
Private (ref)	-	-
Medicare	0.73	0.33, 1.63
Medicaid	0.67	0.39, 1.14
Uninsured/self	1.16	0.68, 1.99
Other	0.30	0.07, 1.23
Presenting level of pain
None	-	-
Mild	2.57	0.99, 6.65
Moderate	1.43	0.54, 3.81
Severe (ref)	2.96	1.14, 7.65
Triage
<15 minutes (ref)	2.41	1.08, 5.37
15–60 minutes	2.01	1.01, 4.01
1–2 hours	1.91	0.88, 4.13
2–24 hours	-	-
Hospital Characteristics
Region
Northeast (ref)
Midwest	0.71	0.42, 1.19
South	0.50	0.29, 0.85
West	0.38	0.20, 0.74
SMSA
Rural	0.34	0.19, 0.61
Urban (ref)	-	-
Safety-net hospital
Yes	0.68	0.43, 1.07
No (ref)	-	-
Teaching hospital
Yes	0.64	0.31, 1.31
No (ref)	-	-
Provider type
Physician (ref)	-	-
Resident	1.38	0.60, 3.20
Other	0.19	0.07, 0.53
NHAMCS ED 2005–2007 adult, non-pregnant visits, with primary reason for visit of flank pain/kidney pain

HNAMCS = National Ambulatory Medical Care Survey; SMSA = Standard Metropolitan Statistical Area