Baseline Characteristics*
| Characteristics | All values, n = 675 |
|---|---|
| General | |
| Age in years, mean ± SD | 66.4 ± 7.6 |
| Male, n (%) | 274 (41) |
| BMI, mean ± SD | 27.5 ± 4.7 |
| <Low education level, n (%) | 279 (41) |
| Smoking, n (%) | 122 (18) |
| Back pain | |
| Duration of back pain, n (%) | |
| <1 week | 62 (9) |
| 1 week–6 weeks | 273 (40) |
| 6 weeks–3 months | 104 (15) |
| >3 months | 156 (23) |
| Average back pain previous week (NRS), mean ± SD | 5.2 ± 2.7 |
| Radiating pain in the leg below the knee, n (%) | 205 (30) |
| Disability (RMDQ), mean ± SD | 9.8 ± 5.8 |
| History of back pain, n (%) | 579 (86) |
| Back surgery in the past, n (%) | 56 (8) |
| Comorbidity musculoskeletal complaints, n (%) | 519 (77) |
| Medical consumption | |
| Use of pain medication for back pain, n (%) | 485 (72) |
| Care from a physical therapist, n (%) | 299 (44) |
| Psychological factors | |
| Patients' expectation to recover of back pain, n (%) | 291 (43) |
| Quality of life (SF-36) physical summary scale, mean ± SD | 43.2 ± 8.9 |
| Quality of life (SF-36) mental summary scale, mean ± SD | 49.6 ± 10.3 |
| Depressive symptomatology (CES-D), mean ± SD | 10.0 ± 7.8 |
| Kinesiophobia (FABQ), physical activity subscale, mean ± SD | 13.4 ± 5.8 |
| Pain catastrophizing (PCS), mean ± SD | 14.1 ± 10.6 |
| Attitude and beliefs about back pain (BBQ), mean ± SD | 26.4 ± 7.2 |
↵* BMI, body mass index (kg/m2); CI, confidence interval; NRS, numeric rating scale (range, 0 to 10); RMDQ, Roland Morris disability questionnaire (range, 0 to 24); SF-36, Short Form-36; physical and mental summary scale (range, 0 to 100); CES-D, Center for Epidemiologic Studies Depression Scale (range, 0 to 60); FABQ, Fear-avoidance beliefs questionnaire, physical subscale (range, 0 to 28); PCS, Pain Catastrophizing Scale (range, 0 to 52); BBQ, Back beliefs questionnaire (range, 9 to 45).