Table 1 Baseline characteristics before and after propensity matching

N

380

1,931

378

378

Age*

60.8 (14.6)

56.5 (14.9)

0.292 (< 0.001)

60.8 (14.6)

60.9 (14.3)

0.009 (0.904)

BMI*

30.6 (6.3)

30.4 (6.5)

0.024 (0.73)

30.6 (6.3)

30.0 (6.3)

0.107 (0.226)

Female

239 (63%)

998 (52%)

0.228 (< 0.001)

237 (63%)

194 (51%)

0.231 (0.002)

Male

141 (37%)

932 (48%)

0.227 (< 0.001)

141 (37%)

183 (48%)

0.226 (0.002)

Not Hispanic or Latino

343 (90%)

1704 (88%)

0.065 (0.258)

341 (90%)

342 (90%)

0.009 (0.902)

Hispanic or Latino

≤ 10 (3%)

30 (2%)

0.075 (0.141)

≤ 10 (3%)

≤ 10 (3%)

0 (1)

American Indian or Alaska Native

0 (0%)

11 (1%)

0.107 (0.14)

0 (0%)

≤ 10 (3%)

0.233 (0.001)

Asian

0 (0%)

28 (1%)

0.172 (0.018)

0 (0%)

≤ 10 (3%)

0.233 (0.001)

Black or African American

0 (0%)

27 (1%)

0.168 (0.02)

0 (0%)

≤ 10 (3%)

0.233 (0.001)

Native Hawaiian or Other Pacific Islander

0 (0%)

13 (1%)

0.116 (0.109)

0 (0%)

≤ 10 (3%)

0.233 (0.001)

White

343 (90%)

1683 (87%)

0.098 (0.092)

341 (90%)

340 (90%)

0.009 (0.903)

Other race

≤ 10 (3%)

≤ 10 (1%)

0.170 (< 0.001)

≤ 10 (3%)

≤ 10 (3%)

0 (1)

Nicotine dependence*

33 (9%)

271 (14%)

0.169 (0.005)

33 (9%)

35 (9%)

0.018 (0.799)

Spondylolisthesis, lumbar*

≤ 10 (3%)

33 (2%)

0.063 (0.224)

≤ 10 (3%)

≤ 10 (3%)

0 (1)

Spondylolisthesis, lumbosacral*

≤ 10 (3%)

≤ 10 (1%)

0.170 (< 0.001)

≤ 10 (3%)

≤ 10 (3%)

0 (1)

Chiropractic manipulative treatment

310 (82%)

114 (6%)

2.359 (< 0.001)

309 (82%)

39 (10%)

2.054 (< 0.001)

Computed tomography, lumbar spine

≤ 10 (3%)

65 (3%)

0.043 (0.46)

≤ 10 (3%)

14 (4%)

0.060 (0.407)

Magnetic resonance imaging, lumbar

56 (15%)

251 (13%)

0.05 (0.361)

55 (15%)

57 (15%)

0.015 (0.838)

Physical therapy evaluation

23 (6%)

60 (3%)

0.141 (0.005)

21 (6%)

10 (3%)

0.147 (0.044)

Lumbar or sacral transforaminal steroid injection

19 (5%)

130 (7%)

0.074 (0.209)

18 (5%)

30 (8%)

0.130 (0.073)

Lumbar or sacral epidural steroid injection

≤ 10 (3%)

22 (1%)

0.110 (0.023)

≤ 10 (3%)

≤ 10 (3%)

0 (1)

Emergency visit

77 (20%)

400 (21%)

0.011 (0.842)

77 (20%)

71 (19%)

0.040 (0.582)

NSAIDs

193 (51%)

992 (51%)

0.012 (0.835)

192 (51%)

214 (57%)

0.117 (0.109)

Opioid analgesics

187 (49%)

1087 (56%)

0.142 (0.011)

187 (49%)

225 (60%)

0.203 (0.006)

Skeletal muscle relaxants

84 (22%)

553 (29%)

0.151 (0.009)

84 (22%)

108 (29%)

0.146 (0.045)

Gabapentinoids

65 (17%)

406 (21%)

0.100 (0.083)

65 (17%)

93 (25%)

0.183 (0.012)