Table 1

Contributions of the variables to baseline SF-36 Mental Health scores

Correlation (r) with


Quantitative variables

Mean

STD

Baseline SF36-MH

R2

p-value


Baseline bodily pain

3.67

1.12

-0.36

0.130

<0.0001

Age

41.8

10.6

0.15

0.023

0.0121


Baseline SF36-MH

Categorical variables

Category

n

Mean

STD


Sex

Male

166

61.25

19.88

0.002

0.5065

Female

110

62.95

19.35

Workers' compensation

Yes

105

56.15

20.53

0.052

0.0001

No

171

65.47

18.27

Length of episode

<=6 week

54

68.52

18.99

0.033

0.0109

6–26 weeks

133

61.29

17.95

>26 weeks

89

58.88

21.68

0.006

0.2024

Comorbid illnesses

Yes

69

59.36

19.81

No

207

62.78

19.58


R2 from the model including all above variables

0.227


Note: R2 was calculated using the model including only one variable.

SF-36 MH scores range from 0–100, where 100 means "always happy and calm over past month."

280 (surgical+ non-surgical) patients have DNA, four patients, 3 missing baseline SF36-MH and 1 missing baseline bodily pain, were dropped from analysis

In covariate selection, linear regression with backward selection method (p = 0.1) was applied, where baseline Sf36-MH was dependent variables, age, sex, workers' compensation, baseline bodily pain, comorbid illnesses, patient group (nonsurgical vs. surgical), marital status, education, and prior episodes were independent variables, and age, sex and workers' compensation were fixed in the model

Max et al. Molecular Pain 2006 2:14   doi:10.1186/1744-8069-2-14

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