Table 2.

Chronic Low Back Pain Status by Independent Variable for Each Risk Level and All Risk Levels Combined for Those With Completed 6-Month Follow-up

FactorLow risk (n = 1788)Medium risk (n = 2152)High risk (n = 1293)Combined risk levels (N = 5233 )
Total, No.Chronic at 6 mo, No. (%)Total, No.Chronic at 6 mo, No. (%)Total, No.Chronic at 6 mo, No. (%)Total, No.Chronic at 6 mo, No. (%)
Patient characteristics
Age, ya
18-40580104 (18)681188 (28)443214 (48)1704506 (30)
41-60633124 (20)838284 (34)509249 (49)1980657 (33)
≥61575105 (18)633231 (36)341167 (49)1549503 (32)
Sexa,b
Women984176 (18)1254429 (34)791421 (53)30291026 (34)
Men804157 (20)898274 (31)502209 (42)2204640 (29)
Racea,b,c
White1503282 (19)1852581 (31)998456 (46)43531319 (30)
Black or African American18735 (19)20587 (42)217133 (61)609255 (42)
Other, declined, or not available9816 (16)9535 (37)7841 (53)27192 (34)
Ethnicitya
Not Hispanic or Latino1672308 (18)2035662 (33)1184575 (49)48911545 (32)
Hispanic or Latino6012 (20)6020 (33)7138 (54)19170 (37)
Declined or not available5613 (23)5721 (37)3817 (45)15151 (34)
Health insurancea,b
Private insurance965168 (17)1177324 (28)560226 (40)2702718 (27)
Medicaid37067 (18)457183 (40)225121 (54)1052371 (35)
Medicare13445 (34)18789 (48)171108 (63)492242 (49)
Workers’ compensation, self-pay, missing, or other31953 (17)331107 (32)337175 (52)987335 (34)
Body mass indexa,b,d
Normal or underweight, <2542862 (14)425111 (26)246112 (46)1099285 (26)
Overweight, 25 to <30574104 (18)661195 (30)364155 (43)1599454 (28)
Obesity, ≥30711156 (22)959364 (38)638342 (54)2308862 (37)
Missing or unknown7511 (15)10733 (31)4521 (47)22765 (29)
Smokera,b
Not current1378245 (18)1508486 (32)866401 (46)37521132 (30)
Current13842 (30)229100 (44)228138 (61)595280 (47)
Not available27246 (17)415117 (28)19991 (46)886254 (29)
Clinical characteristics
Presenting diagnosisa,b
Axial back pain1476259 (18)1521463 (30)886409 (46)38831131 (29)
Back and leg pain31274 (24)631240 (38)407221 (54)1350535 (40)
Baseline Oswestry Disability Index scorea,b
Minimal, 0-201110192 (17)34978 (22)7023 (33)1529293 (19)
Moderate, 21-40520103 (20)979291 (30)389148 (38)1888542 (29)
Severe, 41-609926 (26)574225 (39)510271 (53)1183522 (44)
Very severe, ≥61183 (17)19381 (42)279166 (59)490250 (51)
Missing or unknown419 (22)5728 (49)4522 (49)14359 (41)
Psychological comorbiditiesb
None1690307 (18)2042656 (32)1209577 (48)49411540 (31)
Depression/anxiety9826 (27)11047 (43)8453 (63)292126 (43)
Practice characteristics
Geographic locationa,b
UPMC1047219 (21)1126388 (34)664327 (49)2837934 (33)
Intermountain Healthcare42460 (14)648184 (28)333135 (41)1405379 (27)
Johns Hopkins Medicine14318 (13)21368 (32)11247 (42)468133 (28)
Boston Medical Center17436 (21)16563 (38)184121 (66)523220 (42)
Area Deprivation Index quartilea
1, Low deprivation52998 (19)595176 (30)382200 (52)1506474 (31)
233963 (19)396125 (32)19987 (44)934275 (29)
347181 (17)582209 (36)328150 (46)1381440 (32)
4, High deprivation44991 (20)579193 (33)384193 (50)1412477 (34)
Guideline-recommended processes of care
Pharamcologic therapiesa,b
Concordant1439249 (17)1405415 (30)845396 (47)36891060 (29)
Nonconcordant34984 (24)747288 (39)448234 (52)1544606 (39)
Diagnostic imaginga,b
Concordant1416254 (18)1616500 (31)956465 (49)39881219 (31)
Nonconcordant37279 (21)536203 (38)337165 (49)1245447 (36)
Back pain subspecialty referrala,b
Concordant1713308 (18)2027634 (31)1160548 (47)49001490 (30)
Nonconcordant7525 (33)12569 (55)13382 (62)333176 (53)
Nonconcordant compositea,b
01106180 (16)1018269 (26)598275 (46)2722724 (27)
1572119 (21)877317 (36)489239 (49)1938675 (35)
210633 (31)240108 (45)189106 (56)535247 (46)
341 (25)179 (53)1710 (59)3820 (53)

Abbreviation: UPMC, University of Pittsburgh Medical Center.

aOverall term was significantly associated with Subgroups for Targeted Treatment Back tool risk level at P < .05.

bOverall term was significant in a univariate logistic regression model controlling for the clustered study design of chronic low back pain status at 6 months in the combined risk levels at P < .05.

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

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