Table 4.

Univariate and multivariate logistic analysis of predicting factors for unsatisfactory outcome of sciatica

		Univariate analysis			Multivariate analysis
Variable	N	OR	95% CI	p Value	OR	95% CI	p Value
Randomisation
Surgery	115	0.96	0.51 to 1.80	0.899
Conservative	116	1.00	–
Gender
Female	75	1.27	0.66 to 2.46	0.472
Male	156	1.00	–
Age
≥40	137	2.22	1.11 to 4.47	0.023	2.36	1.11 to 5.00	0.024
<40	94	1.00	–
Mentally demanding job
Yes	139	1.17	0.57 to 2.37	0.669
No	76	1.00	–
Physical job
Yes	85	1.39	0.71 to 2.70	0.339
No	132	1.00	–
Smoking
Yes	84	1.09	0.57 to 2.09	0.792
No	142	1.00	–
BMI
≥25	125	1.19	0.62 to 2.29	0.605
<25	101	1.00	–
Sciatica provoked by sitting
Yes	180	0.73	0.35 to 1.51	0.397
No	51	1.00	–
Coughing, sneezing
Yes	163	1.06	0.53 to 2.12	0.881
No	68	1.00	–
Bragard's test
Positive	62	1.91	0.97 to 3.74	0.059
Negative	154	1.00	–
Sensory disturbance
Yes	200	1.45	0.47 to 4.47	0.514
No	24	1.00	–
VAS leg pain
≥70	89	2.95	1.54 to 5.64	0.001	2.80	1.39 to 5.62	0.004
<70	142	1.00	–
VAS back pain
≥70	34	1.68	0.74 to 3.80	0.211
<70	196	1.00	–
McGill affective score
High (3–5)	17	6.227	2.23 to 17.38	<0.001	4.48	1.43 to 14.08	0.010
Low (0–2)	209	1.00	–
MRI-level herniation
L5S1	125	0.69	0.37 to 1.31	0.256
L3L4/L4L5	106	1.00	–
MRI-sequester
Yes	84	0.85	0.43 to 1.68	0.643
No	122	1.00	–
SF-36 mental health*
Impaired	66	2.25	1.16 to 4.35	0.014
Not impaired	163	1.00	–
VAS general health
≥70	60	1.36	0.68 to 2.74	0.382
<70	168	1.00	–

Only the numbers of the potential predictors with a p<0.10 in the univariate analysis were shown in the multivariate logistic regression.

*The scores on the SF-36 Mental Health subscale were dichotomised using 1 SD below the Dutch reference population.

BMI, body mass index; VAS, visual analogue scale.