Table 2.

Linear Regression Models to Predict Annual Expenditures (2008$)^a on Ambulatory Visits to US Medical Physicians, Chiropractors, and Physical Therapists for Spine Conditions

	Medical Care		Chiropractic Care		Physical Therapy
	Coefficient (95% CI)	P- value	Coefficient (95% CI)	P- value	Coefficient (95% CI) 1,358	P- value
No. of MEPS Respondents in Sample	7,647		4,507		1,358
Yearb	1.04 (1.02, 1.05)	<0.001	1.02 (1.00, 1.04)	0.06	0.99 (0.96, 1.01)	0.31
Age	1.00 (1.00, 1.00)	0.45	1.00 (1.00, 1.00)	0.72	1.01 (1.00, 1.01)	0.00
Gender
male	1.00 (Reference)		1.00 (Reference)		1.00 (Reference)
female	0.99 (0.92, 1.06)	0.70	1.16 (1.07, 1.27)	0.00	1.22 (1.05, 1.41)	0.01
US Region
Northeast	1.00 (Reference)		1.00 (Reference)		1.00 (Reference)
Midwest	0.90 (0.80, 1.02)	0.09	0.89 (0.78, 1.03)	0.11	0.94 (0.75, 1.18)	0.61
South	0.87 (0.78, 0.97)	0.01	1.02, 0.89, 1.17)	0.81	0.93 (0.75, 1.15)	0.51
West	0.91 (0.80, 1.03)	0.15	0.90 (0.79, 1.03)	0.13	0.82 (0.65, 1.02)	0.08
Rurality
Non-MSA	1.00 (Reference)		1.00 (Reference)		1.00 (Reference)
MSA	1.03 (0.94, 1.13)	0.46	1.44 (1.28, 1.61)	<0.001	1.03 (0.85, 1.24)	0.79
Race/Ethnicity
Hispanic	1.01 (0.88, 1.16)	0.89	0.98 (0.78, 1.23)	0.87	0.73 (0.55, 0.98)	0.04
Non-Hispanic White	1.00 (Reference)		1.00 (Reference)		1.00 (Reference)
Non-Hispanic Black or African American	0.96 (0.85, 1.08)	0.46	1.18 (0.94, 1.47)	0.15	1.02 (0.78, 1.34)	0.87
Other or multiple races	0.89 (0.74, 1.08)	0.24	1.25 (0.99, 1.59)	0.06	1.23 (0.86, 1.75)	0.27
Marital status
married	1.00 (Reference)		1.00 (Reference)		1.00 (Reference)
divorced, separated, or widowed	0.95 (0.87, 1.04)	0.30	1.03 (0.92, 1.16)	0.57	0.97 (0.81, 1.15)	0.71
never married	0.94 (0.83, 1.07)	0.36	1.02 (0.89, 1.17)	0.78	1.07 (0.84, 1.35)	0.59
Employment status
employed	1.00 (Reference)		1.00 (Reference)		1.00 (Reference)
ever unemployed (or retired) during year	1.03 (0.94, 1.13)	0.56	1.00 (0.90, 1.09)	0.92	0.92 (0.77, 1.11)	0.38
Education
high school graduate or less	1.00 (Reference)		1.00 (Reference)		1.00 (Reference)
some college or associate's degree	1.05 (0.94, 1.18)	0.37	1.06 (0.94, 1.19)	0.33	0.88 (0.71, 1.10)	0.27
bachelor’s or graduate degree	1.11 (1.01, 1.23)	0.04	1.04 (0.93, 1.17)	0.49	0.99 (0.82, 1.19)	0.91
Health Insurance Coverage
private	1.36 (1.18, 1.57)	<0.001	1.21 (1.03, 1.43)	0.20	1.02 (0.66,1.57)	0.95
public	1.06 (0.90, 1.25)	0.46	0.97 (0.79, 1.18)	0.74	0.66 (0.41, 1.05)	0.08
uninsured	1.00 (Reference)		1.00 (Reference)		1.00 (Reference)
Any Limitation
No	1.00 (Reference)		1.00 (Reference)		1.00 (Reference)
Yes	1.52 (1.40, 1.65)	<0.001	1.21 (1.10, 1.34)	<0.001	1.23 (1.06, 1.42)	0.07
Self-reported Health Status
Excellent, Very Good, or Good	1.00 (Reference)		1.00 (Reference)		1.00 (Reference)
Fair or Poor	1.36 (1.23, 1.50)	<0.001	1.06 (0.94, 1.20)	0.34	1.12 (0.92, 1.36)	0.25

Abbreviations: MEPS, Medical Expenditure Panel Survey; CI, Confidence Interval

^aLinear regression models predict annual expenditures in hundreds (2008$, log transformed)

^bTest of trend (Year included in models as a categorical variable)