Logo of nihpaAbout Author manuscriptsSubmit a manuscriptHHS Public Access; Author Manuscript; Accepted for publication in peer reviewed journal;
PMC full text:
Spine (Phila Pa 1976). Author manuscript; available in PMC 2014 Dec 6.
Published in final edited form as:
Spine (Phila Pa 1976). 2013 May 15; 38(11): 953–964.
doi:  10.1097/BRS.0b013e3182814ed5

Table 2

Multivariate Model Predicting Lumbar Spine Surgery by Three Years from Baseline Variables

Domain and variablesBivariate OR^Bivariate 95% CIMultivariate OR^^Multivariate 95% CIMultivariate P-Value
Sociodemographics
Age, years (ref= 35–44 years)0.003
 ≤24 years0.150.05 – 0.410.230.07 – 0.73
 25 – 34 years0.420.26 – 0.660.490.27 – 0.89
 45 – 54 years0.860.59 – 1.270.700.41 – 1.18
 ≥ 55 years1.000.61 – 1.661.430.73 – 2.82
Gender (ref=male)0.0001
 Female0.730.51 – 1.040.400.25 – 0.65
Region of worker residence (ref=urban)0.17
 Suburban1.771.16 – 2.692.001.17 – 3.41
 Large town1.020.60 – 1.751.310.65 – 2.64
 Rural1.150.65 – 2.031.080.55 – 2.13
Race/ethnicity (ref=White non-Hispanic)0.002
 Hispanic0.360.20 – 0.670.300.14 – 0.66
 Other0.560.33 – 0.950.510.26 – 0.9991
Employment-related
Fast pace (ref=strongly disagree/disagree)0.25
 Agree1.210.78 – 1.881.450.81 – 2.61
 Strongly agree1.781.16 – 2.741.630.90 – 2.95
Job duration ≥ 6 months0.71
 < 6 months1.380.95 – 1.981.100.68 – 1.77
Employer offered job accommodation (ref=Yes)0.43
 No/don’t know1.771.26 – 2.481.220.74 – 2.01
Returned to paid work by baseline interview (ref=Yes, same job)0.74
 Yes, light duty or different job2.441.25 – 4.761.230.55 – 2.88
 No8.284.72 – 14.561.340.64 – 2.79
Pain and function
Number pain sites (ref=0–2 sites)0.60
 3 – 4 sites5.153.34 – 7.941.340.76 – 2.35
 5 – 8 sites4.222.50 – 7.111.280.65 – 2.52
Pain intensity, past week (0= no pain, ref= 0–3)490.18
 4 – 55.502.42 – 12.482.390.90 – 6.36
 6 – 78.233.68 – 18.371.670.62 – 4.49
 8 – 1015.266.90 – 33.722.360.86 – 6.50
Roland-Morris Disability Questionnaire34 (0=no disability) (ref=0–8)0.0003
 9 – 168.553.02 – 24.192.520.78 – 8.10
 17 – 2431.6911.59 – 86.636.121.84 – 20.42
Pain change since injury (ref=better)0.50
 Same3.312.24 – 4.871.060.62 – 1.80
 Worse6.724.46 – 10.121.560.84 – 2.90
Clinical status
Injury severity (ref=mild strain/sprain)<0.0001
 Major strain/sprain with substantial immobility but no evidence of radiculopathy1.360.78 – 2.380.840.43 – 1.62
 Evidence of radiculopathy7.805.21 – 11.684.342.62 – 7.17
 Reflex, sensory or motor abnormalities11.576.19 – 21.655.732.62 – 12.52
Previous injury (any type) with ≥ 1 month off work (ref=no)0.32
 Yes1.831.32 – 2.541.190.86 – 1.66
Opioid Rx within 6 weeks of injury (ref=no)0.38
 Yes2.461.78 – 3.390.870.65 – 1.18
Health care
Specialty, first provider seen for injury (ref=primary care)<0.0001
 Surgeon10.416.72 – 16.118.695.03 – 15.01
 Occupational medicine2.091.13 – 3.871.390.67 – 2.87
 Chiropractor0.210.10 – 0.450.220.10 – 0.50
 Other1.360.84 – 2.191.380.78 – 2.45
Time from injury to first medical visit for injury (ref=0–6 days)0.32
 7 – 13 days1.080.65 – 1.790.740.39 – 1.40
 ≥ 14 days2.581.67 – 3.981.490.82 – 2.72
Health behavior
Tobacco use (ref=no)0.38
 Occasionally/frequently1.040.64 – 1.670.660.36 – 1.21
 Daily1.491.06 – 2.110.950.60 – 1.50
Psychological
Catastrophizing50 ‡‡ (ref=0–1)0.18
 Low (>1 – <2)3.021.55 – 5.901.750.73 – 4.18
 Moderate (2 – <3)5.302.99 – 9.422.281.05 – 4.93
 High (3 – 4)6.393.57 – 11.432.150.94 – 4.90
Recovery expectations50 (0–10 scale, 10 = extremely certain will be working in 6 months, ref=10)0.38
 High (7 – 9)3.042.10 – 4.400.870.51 – 1.48
 Low (0 – 6)1.861.22 – 2.840.970.56 – 1.67
Blame for injury51 (ref=work)0.09
 Self0.520.31 – 0.850.720.38 – 1.35
 Someone/something else1.250.81 – 1.921.170.67 – 2.06
 Nothing/no one0.910.58 – 1.420.960.52 – 1.76
Work fear-avoidance52 ⋄⋄ (ref= <3, very low)0.27
 Low-moderate (>3 – <5)1.710.93 – 3.161.000.47 – 2.16
 High (5 – 6)3.852.21 – 6.701.470.71 – 3.04
SF-36 v2 Mental Health35 (ref=>50)0.26
 41 – 503.272.05 – 5.201.310.72 – 2.40
 ≤ 403.532.29 – 5.450.870.48 – 1.58

Each baseline variable included in this table was associated (P < 0.10) in bivariate analyses with back surgery by three years after occupational back injury

ref = reference group

^adjusted for age and gender, except for age and gender
^^adjusted for all other variables in the multivariate model
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