Multivariate analyses of the effects (OR) of the exposition variable (disability pension (DP) applicant) and other variables on return to work 12 months after surgery
| Univariate analyses | Multivariate analyses | |||||
| OR | 95% CI OR | P value | OR | 95% CI OR | P value | |
| Planning to apply for DP (yes) | 12.3 | 7.7 to 19.5 | <0.001 | 2.4 | 0.7 to 8.3 | 0.183 |
| Have applied for DP (yes) | 6.3 | 3.8 to 10.4 | <0.001 | 5.9 | 1.7 to 20.7 | 0.006 |
| Age* | 1.0 | 1.0 to 1.0 | 0.005 | 1.0 | 1.0 to 1.0 | 0.308 |
| Female gender* | 1.9 | 1.7 to 2.1 | <0.001 | 2.5 | 1.8 to 3.4 | <0.001 |
| Smoking* (yes/no) | 1.9 | 1.6 to 2.2 | <0.001 | 0.9 | 0.6 to 1.4 | 0.683 |
| College or university education* (yes/no) | 0.5 | 0.4 to 0.5 | <0.001 | 0.7 | 0.5 to 0.9 | 0.020 |
| Native Norwegian speaker* (yes/no) | 1.6 | 1.3 to 2.0 | <0.001 | 1.5 | 0.9 to 2.4 | 0.142 |
| Body mass index* | 1.0 | 1.0 to 1.0 | 0.002 | 1.0 | 1.0 to 1.0 | 0.927 |
| Numeric Rating Scale score for back pain* (0–10) | 1.2 | 1.1 to 1.2 | <0.001 | 1.1 | 1.0 to 1.2 | 0.004 |
| Numeric Rating Scale score for radiating pain* (0–10) | 1.0 | 1.0 to 1.0 | 0.083 | 0.9 | 0.9 to 1.0 | 0.105 |
| Oswestry Disability Index* (0–100) | 1.0 | 1.0 to 1.0 | <0.001 | 1.0 | 1.0 to 1.0 | 0.443 |
| Longer than 12 months duration of back pain* (yes/no) | 1.8 | 1.6 to 2.0 | <0.001 | 1.6 | 1.0 to 2.4 | 0.050 |
| Fusion surgery (yes/no) | 2.1 | 1.5 to 2.9 | <0.001 | 1.5 | 0.9 to 2.3 | 0.102 |
| Use of painkillers* (yes/no) | 1.7 | 1.4 to 2.0 | <0.001 | 1.3 | 0.8 to 2.0 | 0.299 |
| Previous lumbar spine surgery* | 0.8 | 0.6 to 1.1 | 0.111 | 0.8 | 0.5 to 1.1 | 0.149 |
| Any comorbidity* (yes/no) | 1.7 | 1.5 to 2.0 | <0.001 | 1.3 | 0.9 to 1.9 | 0.101 |
| American Society of Anaesthesiologists′ classification* >2 (yes/no) | 1.6 | 1.2 to 2.2 | 0.004 | 1.2 | 0.6 to 2.3 | 0.544 |
| Moderate to severe anxiety and/or depression*‡ (yes/no) | 1.0 | 0.9 to 1.2 | 0.677 | 0.9 | 0.7 to 1.3 | 0.604 |
| Reading/writing difficulties† (yes/no) | 1.5 | 1.1 to 2.1 | 0.004 | 1.1 | 0.8 to 1.7 | 0.556 |
| Wanted back to work by employer†§ (1–3) (yes/uncertain/no) | 2.5 | 2.0 to 3.2 | <0.001 | 1.9 | 1.4 to 2.6 | <0.001 |
| Heavy physical work† (0–10) | 1.2 | 1.1 to 1.2 | <0.001 | 1.1 | 1.0 to 1.1 | 0.003 |
| ÖMPQ item no 15†¶ (0–10) | 1.0 | 1.0 to 1.1 | 0.128 | 1.0 | 0.9 to 1.0 | 0.456 |
| ÖMPQ item no 16†** (0–10) | 0.8 | 0.8 to 0.9 | <0.001 | 0.9 | 0.9 to 1.0 | <0.001 |
| ÖMPQ item no 19†, †† (0–10) | 1.0 | 1.0 to 1.1 | 0.033 | 1.0 | 0.9 to 1.0 | 0.186 |
| ÖMPQ item no 20†‡‡ (0–10) | 1.2 | 1.2 to 1.2 | <0.001 | 1.2 | 1.1 to 1.3 | <0.001 |
Patients with a preoperative sick leave less than 12 months are included.
*Variables from 2009-2020: n=806 DP-applicants, n=15291 non-applicants.
†Variables from 2019 to 2020 only: n=122 DP-applicants, n=2412 non-applicants.
‡EQ-5D fifth item.
§'Do you feel that your employer wants you back to work?’.
¶ ‘In your view, how large is the risk that your current pain may become persistent?’ (no risk -very large risk).
**'In your estimation, what are the chances you will be working your normal duties in 6 months’ (no change-very large chance).
††'An increase in pain is an indication that I should stop what I’m doing until the pain decreases’ (completely disagree-completely agree).
‡‡'I should not do my normal work with my present pain’ (completely disagree-completely agree).
EQ-5D, EuroQol five-dimension; ÖMPQ, Örebro Musculoskeletal Pain Questionnaire.