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Table 2 Logistic regression on the probability of 30% responseNegative values indicate reduced probability of 30% response.

From: Predicting long-term response to strong opioids in patients with low back pain: findings from a randomized, controlled trial of transdermal fentanyl and morphine

Variable (baseline value)

Effect estimate

p Value of Type III effect

Category (p value)

Odds ratio

95% CI

Age

-0.0007

0.9350

 

0.999

0.98–1.02

Mental health

0.0045

0.2935

 

1.004

1.00–1.01

Pain at rest

-0.3612

0.1779

Moderate1 (0.0633)

0.697

0.48–1.02

Compared with no/slight pain

-0.2503

 

Severe1 (0.2783)

0.779

0.50–1.22

Pain on movement

-0.1683

0.6717

Moderate2 (0.6788)

0.845

0.38–1.87

Compared with no/slight pain

-0.2926

 

Severe2 (0.4652)

0.746

0.34–1.64

Physical functioning (SF-36)

-0.0055

0.2270

 

0.995

0.99–1.00

Social functioning (SF-36)

-0.0036

0.3129

 

0.996

0.99–1.00

Duration of pain

-0.0006

0.4152

 

0.999

0.99–1.00

Education

-0.2680

0.5083

Apprenticeship3 (0.3462)

0.765

0.44–1.34

Compared with primary education

0.0649

 

Secondary education3 (0.7356)

1.07

0.73–1.56

 

0.2464

 

Higher education3 (0.4168)

1.28

0.71–2.32

Employment

-0.1039

0.0582

Employed4 (0.6751)

0.901

0.55–1.47

Categories compared with disabled

-0.8852

 

Non-professional4 (0.0029)

0.413

0.23–0.74

 

-0.2908

 

Retired4 (0.2201)

0.748

0.47–1.19

 

-0.2739

 

Student4 (0.4163)

0.760

0.39–1.47

High dose

0.7185

0.0499

 

2.051

1.00–4.21

Neuropathic pain

-0.1857

0.2735

 

0.831

0.60–1.16

Treatment group

0.0530

0.7434

 

1.054

0.77–1.45

Sex

0.0439

0.8033

 

1.045

0.74–1.48