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Table 4 Significant Prognostic Factors identified in all included studies

From: Prognostic factors in non-surgically treated sciatica: A systematic review

ID First Author Statistical analysis Outcomes measured Statistically significantapredictors of poor outcome Strength of association Statistically significantapredictors of good outcome Strength of association Comments
1 Balague [12] Multivariate analysis (stepwise logistic regression) "Recovery" (composite score including pain, disability & muscle strength)
Recovery defined as:
ODI Score ≤ 20
VAS pain ≤ 15
Normal muscle strength test (score 5)
Positive neurological examination
OR 4.3
(95%CI; 1.37, 13.28)
   It is unclear whether the odds ratio given is crude or adjusted.
2 Beauvais [13] Recovery and failure groups compared using Fishers test, Chi squared test or Wilcoxon test "Recovery"
Complete = return to usual work/activities, little or no analgesia
Partial = residual pain, frequent analgesic use, complete or partial return to work, limited athletic activities
Failure = persistent pain, continuous analgesic use, unable to return to work
Hospital admission because of severity of sciatic pain Not reported    
3 Carragee [14] Multivariate analysis (multiple logistic regression) Composite measure of overall outcome comprising sum of scores on 0-10 scale for self-reported pain, medication use, activity restriction and satisfaction, total divided by 4 to give outcome score
> 6 = good
≤6 = poor
Larger ratio of disc to remaining canal (in conservatively treated patients) R = 0.50 Shorter duration of symptoms
Absence of litigation
Younger age
Not reported Data from surgically and non-surgically treated patients analysed separately. Only data from conservatively treated patients presented
4 Hasenbring [15] Multivariate regression analysis Pain Intensity
Self report
8 point scale
Lesser degree of disc displacement
High score for non-verbal pain behaviour Low score for direct search for social support
Tendency to ignore pain experience
Poor ability to imagine coping with the pain
Low social status
β = -0.32
β = 0.15
β = 0.31
β = -0.35
β = 0.29
β = -0.20
β = -0.17
   Pain intensity was the only outcome studied.
73 (65.8%) underwent surgical treatment but the analysis adjusted for treatment which was not found to be a significant predictor in this study.
5 Jensen [16] Multivariate analysis adjusted for age, sex and treatment "Recovery" (composite score including pain on 11 point VRS & disability on RMDQ)
Recovery defined as:
Pain score < 1 & RMDQ ≤ 3
   Broad based disc protrusion
Disc extrusion
Male gender
Absence of canal stenosis (males only)
OR 13.6
(95% CI; 1.9, 95.4)
OR 10.6
(95% CI; 1.9, 58.7)
OR 2.6
(95% CI; 1.3, 5.0)
OR 4.2
(95% CI; 1.2, 14.7)
6 Komori [17] Non-parametric methods (not further specified) Outcome defined according to residual self-reported symptoms and disability on 3 point scale (poor, fair, good) Smaller herniated disc
Greater symptom severity at initial assessment
Not reported    The findings of this study should be interpreted with caution due to poor methodological quality
7 Miranda [19] Multivariate logistic regression Outcome defined as persistence of pain based on self report of sciatic pain
Persistence = sciatica pain on >30 days/year in 2 consecutive years (1994 & 1995) on modified NMQ)
Poor job satisfaction
OR 2.8
(95% CI; 1.2,6.7)
OR 2.3
(95% CI; 1.3,4.3)
OR 3.9
( 95% CI;1.4,10.7)
   Diagnosis of sciatica based on self-reported symptoms only
8 Vroomen [18] Multivariate logistic regression Poor outcome defined as absence of any improvement at 3 months based on self-reported change in symptoms Duration of pain > 30 days
Positive SLR
OR 10
OR 2.5
(95%CI;1.25,20)* *
see footnote
   Patients undergoing eventual surgery excluded from this analysis.
Follow up period only 3 months.
  1. * We have recalculated the odds ratios for poor outcome from the original report of the analysis of patients treated conservatively throughout p < 0.05