Table 1 Outcome and predictor variables
| Â | Outcome measurement tool | Logistic multivariable analysis categories | ||||
|---|---|---|---|---|---|---|
Outcome variables (Pre-operative/6 months) | ||||||
Physical function | Oswestry Disability Questionnaire (ODQ) (0–100) | 1. <SCB (18.8) | 2. ≥ SCB (18.8) | |||
|  | SF-36 Physical Component Summary (SF-36 PCS) (0–100) | 1. <SCB (− 6.2) | 2. ≥ SCB (−6.2) | |||
Back Pain | Numerical pain rating scale (NRPS) (0–10) | 1. <SCB (2.5) | 2. ≥SCB (2.5) | |||
Leg Pain | Numerical pain rating scale (NRPS) (0–10) | 1. <SCB (2.5) | 2. ≥SCB (2.5) | |||
Predictor variables | ||||||
Total walking time (1st 7 post-op days) | ActivPAL3 accelerometer | Hours (continuous) | ||||
Age | – | 1. < 65 years | 2. ≥65 years | |||
Sex | – | 1. Male | 2. Female | |||
Current smoking status | – | 1. Non-smoker | 2. Smoker | |||
Obesity | Body Mass Index (BMI) | 1. BMI < 30 | 2. BMI ≥30 | |||
Diabetes | – | 1. Not diabetic | 2. Diabetic | |||
Depression | Patient Health Questionnaire Depression Scale (PHQ-9) | 1. No depression: PHQ-9 < 10 | 2. Increased likelihood of depression: PHQ-9 ≥ 10 | |||
Anxiety | Generalised Anxiety Disorder 7 Item Scale (GAD-7) | 1. No anxiety: PHQ-9 < 10 | 2. Increased likelihood of anxiety: PHQ-9 ≥ 10 | |||
Pre-operative pain duration | – | 1. < 12 months | 2. ≥12 months | |||
Neurological deficit | Self-report | 1. No deficit | 2. Sensory/motor deficit | |||
Pre-operative activity | International Physical Activity Questionnaire Short Form (IPAQ-SF) | 1. Moderate/high activity | 2. Low activity | |||
Pre-operative mobility | ODQ, Section 4 (restricted mobility: score ≥ 3: unable to walk more than 500 m, or requires a stick, crutches or other support) | 1. Unrestricted mobility | 2. Restricted mobility | |||
Pre-operative function | ODQ classification (%) | 1. 0–20% | 2. 21–40% | 3. 41–60% | 4. 61–80% | 5. 81–100% |
Surgical procedure | – | 1. Decompression | 2. Discectomy | 3. Fusion | ||
Number of vertebral levels | – | 1. Single level | 2. Multi-level | |||