Table 2.

Baseline comparison of patients who received surgery within 6 months of enrollment and those who did not.

Factor	Level	Non-surgical (n=409)	Surgical (n=86)	p-value between groups
Demographics
Sex, %	Male	48	45	0.67
	female	52	55
Education, %	High school or less	27	25	0.62
	Some College	40	46
	College degree	32	29
Race, %	White	84	87	0.45
	Other	16	13
Age, mean (sd)a, years		42.7 (9.3)	42.1 (8.7)	0.60
Work status, %	Working full or part time	50	47	0.06
	On leave, unemployed	24	29
	Homemaker, student, retired	9	15
	Disabled	17	8
Clinical characteristics
Duration, %	Less than 12 month	17	14	0.67
	1-5 years	47	52
	5+ year	35	34
Previous surgery, %	Yes	21	36	0.004
BMI, %	<24.9	36	29	0.51
	25.9-29.9	36	41
	30.0+	28	29
Comorbidity in Charlson index, %	Any	36	41	0.43
Smoker, %	Yes	29	21	0.12
Excessive alcohol/drug screen, %	Positiveb	12	13	0.83
Setting
Enrollment site, %	County medical center	37	26	0.08
	Academic affiliate	22	22
	Private hospital affiliate	41	52
Baseline physical health measuresc
Roland Score, mean (sd)	0-23	15.9 (5.4)	17.7 (4.2)	0.003
SF-36v.2 Physical function, mean (sd)	Norm-based (0-100)	32.9 (10.7)	28.8 (9.2)	<0.001
Overall Pain Rating, mean (sd)	0-10	6.1 (2.3)	6.5 (1.9)	0.10
Back pain bothersomeness, mean (sd)	1-5	4.0 (0.9)	4.4 (0.7)	0.03
Leg pain bothersomeness, mean (sd)	1-5	3.0 (1.4)	3.5 (1.3)	0.01
Baseline mental health measuresc
SF-36v.2 Mental Health, mean (sd)	Norm-based (0-100)	42.2 (12.1)	42.2 (12.3)	0.96
Pain Catastrophizing, mean (sd)	Raw score (0-52)	23.2 (13.4)	25.3 (13.3)	0.20
SCL-90 Somatization, mean (sd)	Raw score (0-4)	1.2 (0.6)	1.1 (0.6)	0.80
SCL-90 Depression, mean (sd)	Raw score (0-4)	1.1 (0.9)	1.1 (0.9)	0.58

^asd: standard deviation

^bPositive alcohol/drug screen was “yes” to either of two questions: excessive use within the past year or desire to cut down.

^cHigher scores indicate worse pain and function on all outcome measures except the SF-36 Physical Function and Mental Health scales, where higher scores indicate better function.