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. 2013 Apr 19;14:140. doi: 10.1186/1471-2474-14-140

Table 2.

Baseline variables and logistic regression analyses of univariables

 
  
 One-year U-RTW 1
Variables Baseline OR 95% CI P
Clinical variables
  
  
  
  
Sex: female/all (% female), reference female
 166/325 (51)
 0.74
 0.47-1.66
 0.196
Agew: mean (SD, range), reference 18 years
 41.7 (10.4, 18-60)
 1.00
 0.98-1.02
 0.743
Body Mass Index (BMI): mean (SD, range), ref. 18 kg/m2
 26.7 (5.0, 18-53)
 1.01
 0.97-1.06
 0.597
No with radiculopathy/all, n (%), ref. non-specific
 111/325 (34)
 1.06
 0.65-1.72
 0.829
Low back pain classification, n (%) overall p
  
  
  
 0.011
 Non-specific LBP without radiation below the knee
 96 (30)
 1
  
 Non-specific LBP with pain below the kneew
 118 (36)
 2.19
 1.21-3.97
 Radiculopathyw
 111 (34)
 1.87
 1.00-3.50
Intensity of back pain2p, mean (SD, range), ref. 0
 17.6 (6.3, 0-30)
 1.12
 1.08-1.17
 <0.001
Intensity of leg pain2, mean (SD, range), ref. 0
 14.2 (8.3, 0-30)
 1.06
 1.03-1.09
 <0.001
Pain score2p (back + leg pain), mean (SD, range), ref. 3
 32.0 (12.2, 3-60)
 1.06
 1.04-1.08
 <0.001
Duration of actual painp: ref. ≤ 3 months (%)
 (51)
 1.35
 0.85-2.13
 0.200
Use of pain medication: (%5-7 days/week), ref. less often
 (58)
 1.75
 1.09-2.80
 0.021
Disability (Roland Morris)w: median (range), ref. 3
 16 (3-23)
 1.19
 1.03-1.16
 0.003
No ‘much bothered by widespread painp the preceding two weeks’/all, n
  
  
  
  
(%), reference: ‘not much bothered’
 53/325 (16)
 1.43
 0.77-2.66
 0.254
Forward-flexion (Mod. Schober): mean (SD, range), ref. 0.5 cm
 5.3 (1.6, 0.5-10)
 0.96
 0.83-1.11
 0.574
Side-flexionp: mean (SD, range), reference 4 cm
 13.7 (3.8, 4-26.5)
 0.89
 0.83-0.95
 <0.001
Tender pointsp: median (range), reference 0
 5 (0-18)
 1.07
 1.01-1.13
 0.017
Disc Degenerat. Score L1-4: 0-12, median (range), ref. 0
 1 (0-8)
 0.95
 0.80-1.12
 0.521
Disc herniationp L4-5 without radiculopathy, ref. none
 12/325 (4)
 0.863
 0.24-3.04
 0.818
Disc herniationp L5-S1 without radiculopathy, ref. none
 14/325 (4)
 1.553
 0.52-4.61
 0.427
Psychosocial and life style variables
  
  
  
  
Fear avoidancew: (0-30), dichotomised, reference <28
 25 (3-30)
 1.62
 1.27-2.06
 <0.001
Waddell’s signsw: n/all (% with one or more), ref. none
 78/325 (24)
 2.33
 1.37-3.97
 0.002
Bodily distressw: 0-11, median (range), ref. 0
 3 (0-11)
 1.19
 1.08-1.30
 <0.001
Worrying and health anxietyw: 0-7, median (range), ref. 0
 2 (0-7)
 1.13
 1.01-1.27
 0.039
Mental distressw: 0-8, median (range), ref. 0
 1 (0-8)
 1.13
 1.03-1.24
 0.011
Depressive symptomw: 0-6, median (range), ref. 0
 0 (0-6)
 1.23
 1.08-1.40
 0.002
General health perceived as badw/all, reference: splendid, very good, good
  
  
  
  
or not so good
 33/322 (10)
 3.25
 1.53-6.89
 0.002
No ‘blaming work for low back painp’/ all, n (%), ref. ‘not blaming work
  
  
  
  
or only partly blaming work’
 70/315 (22)
 2.40
 1.40-4.12
 0.002
No ‘not convinced about return to work within 6 monthsw’/all, n (%), ref.
  
  
  
  
‘convinced about return to work’
 119/323 (37)
 3.69
 2.27-6.00
 <0.001
No with compensation claimw/all, n (%), ref. no claim
 77/316 (24)
 2.16
 1.27-3.65
 0.004
School educationp, n (%) overall p
  
  
  
 0.353
 < 10 years
 99 (31)
 1
  
 10 years
 120 (37)
 0.69
 0.40-1.21
 high school or alike
 70 (22)
 0.60
 0.31-1.18
 something else
 33 (10)
 0.55
 0.23-1.28
Vocational education, n (%) overall p
  
  
  
 0.611
 none
 55 (17)
 1
  
 unskilled, one or more courses
 41 (13)
 1.12
 0.49-2.59
 skilled education, craftsman, clerk
 110 (35)
 0.74
 0.38-1.45
 short and intermediate education < 4 years
 81 (25)
 0.67
 0.33-1.37
 long education > 4 years
 8 (3)
 0.38
 0.07-2.07
Marital status overall p
  
  
  
 0.085
married
 158 (49)
 1
  
 living together, not married
 85 (27)
 1.26
 0.72-2.23
 alone, not previously living together
 12 (4)
 0.17
 0.02-1.38
 alone (previous married or living together)
 48 (15)
 1.41
 0.72-2.73
 something else
 16 (5)
 3.10
 1.05-9.16
No with no children/all, n (%), ref. having children
 71/320 (22)
 0.91
 0.50-1.66
 0.755
No with no home ownership/all, n (%), ref. home ownership
 108/318 (34)
 2.61
 1.60-4.27
 <0.001
Jobw overall p
  
  
  
 0.978
 unskilled
 104 (33)
 1
  
 skilled
 73 (23)
 1.11
 0.60-2.07
 salaried employee
 66 (21)
 1.00
 0.51-1.95
 independent
 17 (5)
 0.76
 0.25-2.34
 something else
 56 (18)
 1.04
 0.52-2.06
Job: No leader/all, n (%), ref. not leader
 37/308 (12)
 0.49
 0.22-1.10
 0.085
Personal incomep €, n (%) overall p
  
  
  
 0.019
 <20,137
 33 (11)
 1
  
 20,137-33,561
 153 (50)
 0.57
 0.26-1.24
 33,562-50,341
 99 (32)
 0.34
 0.14-0.79
 >50,341
 22 (7)
 0.18
 0.05-0.67
Income of family €, n (%) overall p
  
  
  
 0.278
 < 33,562
 46 (16)
 1
  
 33,562-50,341
 70 (25)
 1.52
 0.71-3.26
 50,342-67,123
 106 (37)
 0.91
 0.44-1.87
 > 67,123
 63 (22)
 0.48
 0.21-1.11
Smokingp, n (%) overall p
  
  
  
 0.065
 never smoking
 101 (31)
 1
  
 previously smoking
 85 (26)
 1.41
 0.76-2.63
 smoking currently
 136 (42)
 1.93
 1.11-3.36
No drinking alcohol less than once per monthp/all, n (%), ref. drinking
  
  
  
regularly, at least once/month
 77/322 (24)
 1.76
 1.03-2.98
 0.037
Exercise in leisure timep, dichotomised
  
  
  
Vigorous or regular exercise several times a week including heavy
  
  
  
gardening or housework, n (%)
 108 (34)
 1
  
Walking, cycling or light exercise some hours a week or no exercise at
  
  
  
all, n (%) 212 (66) 1.27 0.78-2.06 0.340

Outcome: unsuccessful return to work at one year (one-year U-RTW). The analyses adjusted for age and sex, except age and sex.

1 Not succeeding in working for at least 4 weeks up to the one-year date or registered as unemployed for at least 4 weeks up to the one-year date: 124 patients (38.2%).

2 Transformed to VAS scale 0-10: mean back pain 5.9, mean leg pain 4.7 and mean pain score 5.3.

3 Patients not examined by MRI were excluded as the diagnosis requires MRI of the lumbar spine.

w Well-known risk factor. p Potential risk factor.

OR: Odds Ratio. CI: confidence interval.