Table 1 Baseline variables stratified for those receiving or not receiving an imaging referral
Baseline variable | Imaging referral N = 522 | No imaging referral N = 1640 | Standardised difference in means | |
|---|---|---|---|---|
Observed# | CEM-weighted†| |||
Female* (N, %) | 226 (43.3) | 648 (39.5) | 0.1 | 0.0 |
Age* (mean, SD) | 49.4 (14.6) | 41.4 (12.4) | 0.6 | 0.1 |
Back pain intensity* (mean, SD) | 6.7 (2.0) | 6.7 (2.1) | 0.0 | 0.0 |
Leg pain intensity* (mean, SD) | 3.7 (3.2) | 2.5 (2.7) | 0.4 | 0.1 |
Disability* (mean, SD) | 55.1 (23.2) | 54.2 (24.3) | 0.0 | 0.0 |
Pain duration* | Â | Â | 0.6 | 0.0 |
 Less than 2 weeks (N, %) | 220 (42.1) | 1131 (69.0) |  |  |
 2 weeks to 3 months (N, %) | 144 (27.6) | 350 (21.3) |  |  |
 Over 3 months (N, %) | 158 (30.3) | 159 (9.7) |  |  |
Expectation of imaging referral (N, %) | 207 (39.7) | 341 (20.8) | Â | Â |
STarT back risk* | Â | Â | 0.3 | 0.0 |
 Low (N, %) | 191 (36.6) | 759 (46.3) |  |  |
 Medium (N, %) | 186 (35.6) | 586 (35.7) |  |  |
 High (N, %) | 145 (27.8) | 295 (18.0) |  |  |
Previous imaging* (N, %) | 143 (27.4) | 434 (26.5) | 0.0 | 0.0 |
Previous surgery* (N, %) | 16 (3.1) | 35 (2.1) | 0.1 | 0.0 |
Previous treatment* (N, %) | 330 (63.2) | 1013 (61.8) | 0.0 | 0.0 |
Presence of any comorbidity (N, %) | 237 (45.4) | 579 (35.3) | Â | Â |
Presence of lumbar spine comorbidity (N, %) | 94 (18.0) | 146 (9.5) | Â | Â |
Suspicion of serious pathology* (N, %) | 24 (4.6) | 7 (0.4) | 0.4 | 0.0 |
Intention to use manipulation* (N, %) | 488 (93.5) | 1596 (97.3) | − 0.2 | 0.0 |