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 1

Return to:   Early Predictors of Lumbar Spine Surgery After Occupational Back Injury

Baseline Variables Associated (P < 0.10) with Lumbar Spine Surgery by Three Years after Claim Receipt for Occupational Back Injury*

Domain and variablesNo surgery (n=1,711)Surgery (n=174)Odds ratio^95% CIP-value
Sociodemographics
Age, years (ref= 35–44 years)50772<0.001
 ≤24 years19440.150.05 – 0.41
 25 – 34 years450270.420.26 – 0.66
 45 – 54 years394480.860.59 – 1.27
 ≥ 55 years166231.000.61 – 1.66
Gender (ref=male)11541280.08
 Female557460.730.51 – 1.04
Region of worker residence (ref=urban)1016900.06
 Suburban257411.771.16 – 2.69
 Large town207181.020.60 – 1.75
 Rural179181.150.65 – 2.03
Race/ethnicity (ref=White non-Hispanic)1173145<0.001
 Hispanic295120.360.20 – 0.67
 Other243170.560.33 – 0.95
Employment-related
Fast pace (ref=strongly disagree/disagree)416350.02
 Agree687631.210.78 – 1.88
 Strongly agree602761.781.16 – 2.74
Job duration ≥ 6 months13191290.09
 < 6 months388451.380.95 – 1.98
Employer offered job accommodation (ref=Yes)800550.001
 No/don’t know9111191.781.27 – 2.49
Returned to paid work by baseline interview (ref=Yes, same job)59314<0.001
 Yes, light duty or different job444252.441.25 – 4.76
 No6731358.284.72 – 14.56
Pain and function
Number pain sites (ref=0–2 sites)84028<0.001
 3 – 4 sites6071105.153.34 – 7.94
 5 – 8 sites264364.222.50 – 7.11
Pain intensity, past week (0= no pain, ref= 0–3)494517<0.001
 4 – 5457385.502.42 – 12.48
 6 – 7456538.233.68 – 18.37
 8 – 103447615.266.90 – 33.72
Pain interference with daily activities, past week (0=no interference, ref=0–3)495877<0.001
 4 – 5384265.802.48 – 13.52
 6 – 73334913.045.82 – 29.26
 8 – 103989819.829.05 – 43.38
Pain interference with work, past week (0=no interference, ref=0–3)496257<0.001
 4 – 5314226.442.72 – 15.29
 6 – 73123911.415.03 – 25.88
 8 – 1044910521.349.80 – 46.48
Roland-Morris Disability Questionnaire34 (0=no disability) (ref=0–8)5244<0.001
 9 – 16601378.553.02 – 24.19
 17 – 2458613331.6911.59 – 86.63
SF-36 v2 Physical Function35 (ref=>50)4458<0.001
 41 – 5032550.850.28 – 2.64
 30 – 40469293.531.59 – 7.83
 < 3047113216.167.77 – 33.62
SF-36 v2 Role Physical35 (ref=>50)4023<0.001
 41 – 5033272.850.73 – 11.13
 30 – 40446298.882.68 – 29.43
 < 3052813533.7110.63 – 106.93
Pain change since injury (ref=better)121365<0.001
 Same325543.312.24 – 4.87
 Worse157546.724.46 – 10.12
Clinical status
Injury severity22†† (ref=mild strain/sprain)99138<0.001
 Major strain/sprain with substantial immobility but no evidence of radiculopathy361201.360.78 – 2.38
 Evidence of radiculopathy306957.805.21 – 11.68
 Reflex, sensory or motor abnormalities432111.576.19 – 21.65
Pain radiates below knee (ref=no)130357<0.001
 Yes4081176.434.58 – 9.05
Previous injury (any type) with ≥ 1 month off work (ref=no)1275100<0.001
 Yes429741.831.32 – 2.54
Opioid Rx within 6 weeks of injury (ref=no)113177<0.001
 Yes541942.461.78 – 3.39
Health care
Specialty, first provider seen for injury (ref=primary care)63545<0.001
 Surgeon987310.416.72 – 16.11
 Occupational medicine107162.091.13 – 3.87
 Chiropractor53480.210.10 – 0.45
 Other337321.360.84 – 2.19
Time from injury to first medical visit for injury (ref=0–6 days)1336119<0.001
 7 – 13 days193201.080.65 – 1.79
 ≥ 14 days138322.581.67 – 3.98
Health behavior
Tobacco use (ref=no)986840.07
 Occasionally/frequently267241.040.64 – 1.67
 Daily505661.491.06 – 2.11
Psychological
Catastrophizing50‡‡ (ref=0–1)55115<0.001
 Low (>1 – <2)282233.021.55 – 5.90
 Moderate (2 – <3)490705.302.99 – 9.42
 High (3 – 4)388666.393.57 – 11.43
Recovery expectations51 (0–10 scale, 10 = extremely certain will be working in 6 months, ref=10)99365<0.001
 High (7 – 9)331653.042.10 – 4.40
 Low (0 – 6)328391.861.22 – 2.84
Blame for injury51 (ref=work)823920.02
 Self339200.520.31 – 0.85
 Someone/something else237331.250.81 – 1.92
 Nothing/no one265280.910.58 – 1.42
Work fear-avoidance52⋄⋄ (ref= <3, very low)36115<0.001
 Low-moderate (>3 – <5)567391.710.93 – 3.16
 High (5 – 6)7831203.852.21 – 6.70
SF-36 v2 Mental Health35 (ref=>50)68830<0.001
 41 – 50417563.272.05 – 5.20
 ≤ 40604883.532.29 – 5.45
ref = reference group

*Missing, “don’t know,” and refusal responses for each variable were combined into one response (unless stated otherwise) for each variable if ≥15 of responses qualified (results not shown). The following variables had missing responses: region of worker residence (n=59), fast pace (6), job duration (4), returned to paid work by baseline interview (1), pain intensity (3), pain interference with daily activities (9), pain interference with work (12), SF-36 v2 Physical Function (1), SF-36 v2 Role Physical (3), pain change since injury (17), injury severity (10), previous injury (any type) with ≥ 1 month off work (7), opioid RX within 6 weeks of injury (42), time from injury to first medical visit for injury (48), tobacco use (3), recovery expectations (64), blame for injury (48), and SF-36 v2 Mental Health (2).
^Age and gender were included in bivariate analyses along with the variable of interest
From the DLI database
By residential zipcode, using the Washington State guidelines classifications at http://www.doh.wa.gov/Data/Guidelines/RuralUrban
Measures self-reported back disability; higher scores indicate more disability
Short-Form-36 version 2 (SF-36v2) Physical Function, Role Physical, and Mental Health scales; higher scores indicate better functioning
††Rated by trained nurses based on medical records early in the claim
‡‡Mean of responses to three questions from the Pain Catastrophizing scale
⋄⋄Mean of responses to two questions from the Fear-Avoidance Beliefs Questionnaire work scale