Table 1.
Baseline characteristics of the total sample of patients and those on sick leave
| Variable | Total sample (n = 559) | Number of responders | Subgroup on sick leave at baseline (n = 275) | Number of Responders |
|---|---|---|---|---|
| Sex, female, n (%) | 263 (47.05) | 559 | 114 (41.45) | 275 |
| Age, years, mean (SD) | 38.90 (10.42) | 559 | 38.68 (10.75) | 275 |
| Body Mass Index, mean (SD) | 25.53 (4.47) | 543 | 25.05 (4.63) | 267 |
| Education after primary school, n (%) | 548 | 268 | ||
| <2 years | 123 (22.45) | 83 (30.97) | ||
| 2–4 years | 370 (67.52) | 167 (62.31) | ||
| >4 years | 32 (5.84) | 6 (2.24) | ||
| Other | 23 (4.20) | 12 (4.48) | ||
| Current smoker, no, n (%) | 299 (54.07) | 553 | 123 (45.56) | 270 |
| Alcohol, ≤7 units/week, n (%) | 412 (76.40) | 540 | 202 (75.94) | 266 |
| Physical activity level leisure, n (%) | 547 | 268 | ||
| Little-some | 424 (77.51) | 225 (83.96) | ||
| Moderate-high | 123 (22.49) | 43 (16.04) | ||
| Sick leave, yes, n (%) | 275 (49.82) | 552 | 275 (100) | 268 |
| Duration of sick leave, weeks, mean (SD) | 12.45 (15.81) | 261 | 12.47 (15.87) | 258 |
| Employment, no, n (%) | 127 (23.09) | 550 | 97 (35.93) | 270 |
| Compensation case, yes, n (%) | 87 (16.35) | 532 | 52 (20.00) | 260 |
| Physical job demands, n (%) | 542 | 263 | ||
| None | 163 (30.07) | 61(23.19) | ||
| Little | 78 (14.39) | 36 (13.69) | ||
| Some | 198 (36.53) | 97 (36.88) | ||
| Heavy | 103 (19.00) | 69 (26.34) | ||
| Physical health, 0–100, mean (SD) | 50.74 (8.45) | 495 | 49.11 (8.03) | 237 |
| Mental health, 0–100, mean (SD) | 49.92 (10.32) | 495 | 47.91 (10.26) | 237 |
| Depression, 0–4, mean (SD) | 1.10 (0.84) | 544 | 1.23 (0.86) | 267 |
| Anxiety, 0–4, mean (SD) | 0.68 (0.66) | 536 | 0.76 (0.67) | 263 |
| Duration of LBPa, <12 months, n (%) | 273 (51.41) | 531 | 148 (56.27) | 263 |
| Pain intensityb, 0–30, mean (SD) | 17.66 (5.66) | 559 | 18.30 (5.62) | 271 |
| Age at first episode of LBPb, years, mean (SD) | 27.79 (11.74) | 542 | 28.87 (11.79) | 261 |
| Family history of LBPa, yes, n (%) | 234 (42.70) | 548 | 118 (45.70) | 270 |
| Disability, 0–23, mean (SD) | 13.75 (4.94) | 559 | 14.62 (4.64) | 275 |
| FAB workc, 0–42, mean (SD) | 24.31 (11.34) | 514 | 29.55 (9.63) | 245 |
| FAB physical activityd, 0–24, mean (SD) | 15.46 (5.34) | 522 | 16.41 (3.33) | 249 |
| Group, intervention, n (%) | 298 (53.31) | 559 | 150 (54.55) | 275 |
SD standard deviation
aLow back pain
bThe back pain questionnaire included 3 separate 11-point numeric rating scales (0–30) comprising the following items: pain at the moment, the worst pain within the past 2 weeks, and the average level of pain within the last 2 weeks. These summed to a total score ranging from 0 points (no back pain at all) to 30 points (worst possible back pain)
cFear avoidance beliefs about work
dFear avoidance beliefs about physical activity