Table 2 Patient reported baseline characteristics for the cohorts of participants with non-specific low back pain
|  | Content validity cohort N = 14 | GLA:D® Back baseline cohort N = 272 | Test–retest cohort N = 37 |
|---|---|---|---|
Age, mean (SD, years) | 56 (8) | 53 (12) | 52 (13) |
Males, N (%) | 3 (21) | 57 (21) | 13 (35) |
Highest achieved education, N (%) | Â | Â | Â |
 No qualification | 0 | 1 (0.4) | 2 (5) |
 Public school | 0 | 14 (5) | 0 (0) |
 High school | 0 | 9 (3) | 0 (0) |
 Vocational training | 10 | 75 (28) | 7 (19) |
 Higher education < 3 years | 1 | 37 (14) | 3 (8) |
 Higher education 3–4 years | 2 | 100 (37) | 18 (49) |
 Higher education > 4 years | 1 | 26 (10) | 6 (16) |
 Missing | 0 | 10 (4) | 1 (3) |
Back pain intensity (0–10 Numeric Rating Scale), mean (SD) | 4.1 (2.1) | 5.0 (2.3) | 5.9 (2.4) |
 Missing (%) | 0 | 1 (0.4) | 0 |
Leg pain intensity (0–10 Numeric Rating Scale), mean (SD) | 7 (5.0)* | 2.8 (2.7) | 3.1 (2.7) |
 Missing (%) | 0 (0) | 0 (0) | 0 (0) |
Episode duration, N (%) | Â | Â | Â |
 0–2 weeks | 0 | 18 (7) |  < 1 week = 5 (14) |
 2–4 weeks | 0 | 11 (4) | 1–4 weeks = 4 (11) |
 4–12 weeks | 2 | 18 (7) | 5 (14) |
 3–12 months | 1 | 52 (19) | 6 (16) |
 > 1 year | 11 | 172 (63) | 17 (46) |
 Missing | 0 | 1 (0.4) | 0 (0) |
Number of previous episodes, N (%) | Â | Â | Â |
 0 episodes | 1 | 67 (25) | 3 (8) |
 1 episode | 1 | 48 (18) | 3 (8) |
 2–3 episodes | 0 | 53 (19) | 6 (16) |
 > 3 episodes | 12 | 103 (38) | 25 (68) |
 Missing | 0 | 1 (0.4) | 0 (0) |
Patient Enablement Instrument for back pain (0–60), mean (SD) |  | 41.8 (10.8) | 39.6 (13.3) |
 Missing, N (%) [any of 6 items missing] |  | 11 (4) | 0 (0) |
STarT Back Tool score, N (%) | Â | Â | Â |
 Low risk [any of 9 items missing] |  | 156 (57) | 19 (51) |
 Medium risk |  | 68 (25) | 8 (22) |
 High risk |  | 48 (18) | 8 (22) |
 Missing (items) |  | 7 (3) | 2 (5) |
 Oswestry Disability Index (0–100), mean (SD) |  | 22.5 (11.6) | 22.4 (15.6) |
 Missing, N (%) [≥ 4 of 10 items missing] |  | 0 (0) | 0 (0) |
 Brief Illness Perception Questionnaire (0–80), mean (SD) |  | 40.7 (11.0) |  |
 Missing, N (%) [≥ 3 of 8 items missing] |  | 2 (1) |  |
 Fear Avoidance Belief Questionnaire—physical activity (0–24), mean (SD) |  | 8.3 (5.4) |  |
 Missing N (%) (any of 4 items missing) |  | 7 (3) |  |
SF-36 subscales | Â | Â | Â |
 Mental health (0–100), mean (SD) |  | 72.4 (16.9) |  |
 Missing, N (%) [any of 5 items missing] |  | 6 (2) |  |
 Social functioning limited by physical health |  | 1.8 (0.9) |  |
 Missing, N (%) |  | 0 (0) |  |