Low back pain: what determines functional outcome at six months? An observational study

Table 6 Multiple regression analysis of predictive variables

Variable	Adjusted odds ratio and 95% confidence interval	Adjusted p-value
Age ^#
≥ 43	1.00
< 43	0.48 (0.23 to 1.02)	0.404
Sex
Female	1.00
Male	1.62 (0.83 to 3.20)	0.161
Ethnicity
White	1.00
Non-white	0.41 (0.18 to 0.96)	0.039
Marital Status
Married/living with partner	1.00
Single/divorced/separated/widowed	1.93 (0.98 to 3.79)	0.056
Physical Activity
Low	1.00
Medium	1.76 (0.80 to 3.85)
High	1.43 (0.55 to 3.84)	0.258
Age at leaving full time education ^#
18 years or under	1.00
Over 18	1.54 (0.77 to 3.09)	0.120
Zung depression ^#
≥ 23	1.00
< 23	1.97 (0.80 to 4.83)	0.975
Modified Somatic Perception score ^#
≥ 8	1.00
< 8	0.75 (0.33 to 1.70)	0.876
In paid employment
No	1.00
Yes	0.98 (0.45 to 2.17)	0.967
Duration of current episode
3 months or less	1.00
Over 3 months	0.55 (0.24 to 1.28)	0.438
Episodes over past 12 months
Continuous/on-off	1.00
Episodic	2.64 (1.25 to 5.60)	0.005
Length of usual episode
12 weeks or less	1.00
Over 12 weeks	1.03 (0.43 to 2.50)	0.587
Days of pain in last month
28 days or more	1.00
Less than 28 days	1.02 (0.45 to 2.33)	0.730
Von Korff Pain Scale Grade:
0 pain free	-
I low disability/low intensity	1.00
II low disability/high intensity	0.33 (0.131 to 0.86)
III high disability/-moderately limiting	0.97 (0.36 to 2.60)
IV high disability/severely limiting	0.19 (0.04 to 0.92)	0.354
SF-36 Physical Functioning ^#
≥ 50	1.00
< 50	0.54 (0.20 to 1.41)	0.301
Baseline Roland Morris ^#
≥ 11	1.00
< 11	1.95 (0.78 to 4.85)	0.249

Odds Ratios with 95% confidence interval for recovery including variables with unadjusted p-values of less than 0.1 in the univariate analysis, adjusted for all variables in table.
Variables denoted with "#" have been dichotomised from a continuous scale in relation to the relevant median.

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