Table 1.

Descriptive Summary of the Inception Cohort

CharacteristicNo. (%)P value
Overall sample (N = 9547)Missing 6-mo follow-up (n = 4314)Completed 6-mo follow-up (n = 5233)
Patient characteristics
Age, y
18-402986 (31)1282 (30)1704 (33).01
41-603697 (39)1717 (40)1980 (38)
≥612859 (30)1310 (30)1549 (30)
Sex
Women5502 (58)2473 (57)3029 (58).63
Men4040 (42)1836 (43)2204 (42)
Race
White7587 (80)3234 (75)4353 (83)<.001
Black or African American1321 (14)712 (17)609 (12)
Other, declined, or not availablea634 (7)363 (8)271 (5)
Ethnicity
Not Hispanic or Latino8849 (93)3958 (92)4891 (93).005
Hispanic or Latino404 (4)213 (5)191 (4)
Declined or not available289 (3)138 (3)151 (3)

Health insurance
Private4888 (51)2186 (51)2702 (52).27
Medicaid869 (9)377 (9)492 (9)
Medicare 1923 (20)871 (20)1052 (20)
Workers’ compensation, self-pay, missing, or other1862 (20)875 (20)987 (19)

Body mass indexb
Normal or underweight, <251871 (20)772 (18)1099 (21)<.001
Overweight, 25 to <302668 (28)1069 (25)1599 (31)
Obesity, ≥303757 (39)1449 (34)2308 (44)
Missing or unknown1246 (13)1019 (24)227 (4)

Smoking
Not current6188 (65)2436 (57)3752 (72)<.001
Current1125 (12)530 (12)595 (11)
Not available2229 (23)1343 (31)886 (17)
Clinical characteristics
Presenting diagnosis
Axial back pain7111 (75)3228 (75)3883 (74).43
Back and leg pain2431 (25)1081 (25)1350 (26)
SBT risk level
Low3460 (36)1672 (39)1788 (34)<.001
Medium3783 (40)1631 (38)2152 (41)
High2299 (24)1006 (23)1293 (25)
Baseline Oswestry Disability Index score
Minimal, 0-202939 (31)1410 (33)1529 (29).002
Moderate, 21-403364 (35)1476 (34)1888 (36)
Severe, 41-602063 (22)880 (20)1183 (23)
Very severe, ≥61912 (10)422 (10)490 (9)
Missing or unknown264 (3)121 (3)143 (3)
Psychological comorbidities
None8973 (94)4032 (94)4941 (94).07
Depression/anxiety569 (6)277 (6)292 (6)
Practice characteristics
Geographic location
UPMC4907 (51)2070 (48)2837 (54)<.001
Intermountain Healthcare2068 (22)663 (15)1405 (27)
Johns Hopkins Medicine1587 (17)1119 (26)468 (9)
Boston Medical Center980 (10)457 (11)523 (10)
Area deprivation index quartile
1, Low deprivation2761 (29)1255 (29)1506 (29).003
21764 (18)830 (19)934 (18)
32382 (25)1001 (23)1381 (26)
4, High deprivation2635 (28)1223 (28)1412 (27)
Guideline-recommended processes of care
Pharmacologic therapies
Concordant6925 (73)3236 (75)3689 (70)<.001
Nonconcordant2617 (27)1073 (25)1544 (30)
Diagnostic imaging
Concordant7305 (77)3317 (77)3988 (76).37
Nonconcordant2237 (23)992 (23)1245 (24)
Back pain subspecialty referral
Concordant8915 (93)4015 (93)4900 (94).33
Nonconcordant627 (7)294 (7)333 (6)
Nonconcordant composite
05152 (54)2430 (56)2722 (52)<.001
13387 (35)1449 (34)1938 (37)
2915 (10)380 (9)535 (10)
388 (1)50 (1)38 (1)

Abbreviations: SBT, Subgroups for Targeted Treatment Back tool; UPMC, University of Pittsburgh Medical Center.

aOther included American Indian or Alaska Native, Asian, Hawaiian or Pacific Islander, and multirace.

bBody mass index calculated as weight in kilograms divided by height in meters squared.