Table 2. Logistic Regression Results of Low-Value Imaging Predictors for Primary Care Physicians.

Covariates	Adjusted Odds Ratio (95% CI)a
	Back Pain Visits	Headache Visits	Headache Visits Seen by Clinicians Who Also Saw ≥4 Back Pain Visits
Female	1.02 (1.00-1.03)	0.81 (0.80-0.83)	0.80 (0.78-0.82)
Age distribution, y
18-25	1 [Reference]	1 [Reference]	1 [Reference]
26-35	0.88 (0.85-0.91)	1.03 (1.00-1.07)	1.03(0.99-1.08)
36-45	0.85 (0.82-0.88)	1.06 (1.03-1.10)	1.07 (1.02-1.11)
46-55	0.85 (0.82-0.87)	1.07 (1.04-1.11)	1.11 (1.06-1.16)
56-64	0.90 (0.87-0.93)	1.19 (1.15-1.24)	1.27 (1.21-1.32)
Low neighborhood education levelb	1.01 (0.98-1.03)	0.98 (0.85-1.01)	0.98 (0.95-1.02)
High neighborhood poverty levelc	1.00 (0.98-1.02)	0.96 (0.93-0.98)	0.94 (0.91-0.96)
Quarter, continuous	0.99 (0.99-0.99)	0.99 (0.99-0.99)	0.99 (0.99-0.99)
Race/ethnicity
White	1 [Reference]	1 [Reference]	1 [Reference]
Black	0.96 (0.94-0.99)	0.91 (0.89-0.94)	0.87 (0.83-0.90)
Hispanic	1.12 (1.09-1.15)	0.93 (0.90-0.96)	0.87 (0.84-0.91)
Other	0.99 (0.96-1.02)	0.87 (0.84-0.90)	0.85 (0.81-0.89)
US Region
South	1 [Reference]	1 [Reference]	1 [Reference]
Northeast	0.78 (0.76-0.81)	0.92 (0.89-0.96)	0.91 (0.86-0.95)
West	0.81 (0.80-0.83)	0.80 (0.78-0.83)	0.80 (0.77-0.82)
Midwest	0.91 (0.89-0.93)	1.14 (1.11-1.17)	1.18 (1.15-1.21)
Clinician's prior patient received imaging	2.08 (2.04-2.12)	2.20 (2.13-2.25)	1.91 (1.84-1.97)
High rate of low-value back imaging	NA	NA	1.78 (1.69-1.86)
Area under receiver operator curve	0.62	0.59	0.59

Abbreviation: NA, not applicable.

^aStudy sample 1 consisted of visits for low back pain. Study sample 2 consisted of visits for headache. Study sample 3 included physicians who saw patients with both back pain and headache.

^bLow neighborhood education was defined as census block groups in which more than 25% of residents had education levels below high school.

^cHigh neighborhood poverty was defined as census block groups in which more than 10% of residents had incomes below the poverty level.