Table 2 Linear regression of pain intensity after treatment (NPRS) and potential prognostic factors

Simple regression Final multiple regression model b N=122
B (95% CI) P-value B (95% CI) P-value
Emotional distress (HSCL-25) 2.05 (1.49 to 2.60) P < 0.001 1.06 (0.44 to 1.68) P = 0.001
Pre-treatment pain intensity (NPRS) 0.58 (0.45 to 0.71) P < 0.001 0.46 (0.32 to 0.61) P < 0.001
Pre-treatment disability (PSFS) −0.22 (− 0.39 to − 0.05) P = 0.012
Duration of pain
0–3 months ª
4–12 months 0.34 (−0.72 to 1.39) P = 0.528 0.93 (0.07 to 1.78) P = 0.033
> 12 months 0.75 (− 0.18 to 1.69) P = 0.112 0.75 (− 0.01 to 1.50) P = 0.053 c
Use of pain relieving drugs (0,1) 1.62 (0.78 to 2.46) P < 0.001
Concomitant neck pain (0,1) 1.34 (0.65 to 2.03) P < 0.001
Number of painful sites (0,1) 1.09 (0.16 to 2.02) P = 0.022
Age −0.01 (− 0.03 to 0.02) P = 0.508
Sex (0,1) 0.88 (0.12 to 1.64) P = 0.024
BMI 0.09 (−0.02 to 0.20) P = 0.100
Education (0,1) −0.45 (− 1.22 to 0.32) P = 0.250
Work status (0,1) −0.99 (− 1.90 to − 0.09) P = 0.032
Relationship status (0,1) 0.00 (− 0.70 to 0.70) P = 0.997
Smoking (0,1) 0.77 (−0.50 to 2.05) P = 0.233
1. Duration of treatment was not associated with pain intensity after treatment (P = 0.951)
2. a Reference category
3. b Adjusted for age and sex
4. c Before the model was adjusted for age and sex, duration of pain > 12 months was associated with pain intensity after treatment (P < 0.05)
5. NPRS = Numeric Pain Rating Scale. HSCL-25 = Hopkins Symptom Checklist – 25. PSFS = Patient Specific Functional Scale
6. Use of pain relieving drugs (0: < once a week, 1: ≥ once a week). Concomitant neck pain (0: no, 1: yes). Number of painful sites (0: ≤ 2 painful sites, 1: > 2 painful sites). Sex (0: male, 1: female). Education (0: ≤ 13 years, 1: College / University). Work status (0: not working, 1: working full time, part time or being in education). Relationship status (0: not in a relationship, 1: in a relationship). Smoking (0: no, 1: yes)