Table 1 Baseline characteristics of the complete cohort and the validation sample
Variable | Follow-up cohort (n = 238) | Sample cohort (n = 89) | *p-value | |
|---|---|---|---|---|
Age | Mean (SD, range) number of years | 47.3 (14.45, 19-88) | 46.3 (14.46, 19-88) | 0.587 |
Missing | 2 | 1 | ||
Sex | Male | 104 (44) | 40 (45) | 0.840 |
Female | 134 (56) | 49 (55) | ||
Missing | 0 | 0 | ||
Work status | In paid (including self) employment | 183 (77) | 71 (80) | 0.824 |
At home and not looking for work | 8 (3) | 2 (2) | ||
Unemployed because of back pain | 1 (<1) | 0 | ||
Unemployed because of other reasons | 7 (3) | 3 (3) | ||
Retired | 35 (15) | 10 (11) | ||
Student | 4 (2) | 3 (3) | ||
Missing | 0 | 0 | ||
Pain history | < 3 months | 84 (35) | 29 (33) | 0.966 |
≥ 3 months | 154 (65) | 59 (66) | ||
Missing | 1 (<1) | 1 (<1) | ||
Medication usage | Never | 50 (21) | 23 (26) | 0.596 |
Rarely | 53 (22) | 23 (26) | ||
Sometimes | 83 (35) | 26 (29) | ||
Every day | 52 (22) | 17 (19) | ||
Missing | 0 | 0 | ||
BQ | Mean (SD) score | 29.4 (15.41) | 29.2 (15.65) | 0.956 |
Missing | 5 | 2 |