Classification utility of response to IBP domain questions in patients with inflammatory back pain (IBP) (n = 220) or mechanical back pain (MBP) (n = 66).
| Domain | Criteria | No. IBP (%) | No. MBP (%) | OR (95% CI) | p | Sensitivty, % | Specificity, % | LR + (95% CI) | LR − (95% CI) |
|---|---|---|---|---|---|---|---|---|---|
| Morning stiffness | Calin | 199 (90) | 45 (68) | 4.42 (2.23–8.78) | 0.0001 | 90 | 32 | 1.33 (1.12–1.57) | 0.30 (0.18–0.51) |
| 6-item | 95 (48)* | 16 (25)* | 2.80 (1.49–5.25) | 0.001 | 48 | 75 | 1.94 (1.24–3.04) | 0.69 (0.57–0.84) | |
| Response to exercise | Calin | 136 (67) | 21 (38) | 3.43 (1.86–6.36) | 0.0001 | 67 | 63 | 1.80 (1.26–2.55) | 0.52 (0.39–0.69) |
| 6-item | 116 (53)* | 20 (30)* | 2.62 (1.45–4.71) | 0.001 | 53 | 70 | 1.76 (1.19–2.58) | 0.67 (0.54–0.83) | |
| Diurnal variation | 6-item | 99 (49)* | 5 (8) | 10.66 (4.10–27.71) | 0.0001 | 49 | 92 | 5.95 (2.54–13.94) | 0.56 (0.48–0.65) |
| Response to rest | 6-item | 131 (60) | 28 (42) | 2.07 (1.18–3.61) | 0.010 | 60 | 58 | 1.42 (0.69–1.05) | 0.69 (0.53–0.9) |
| Nocturnal pain | 6-item | 97 (51)* | 22 (38)* | 1.71 (0.93–3.12) | 0.080 | 51 | 62 | 1.35 (0.94–1.92) | 0.79 (0.62–1.01) |
| Age of onset (< 40 yrs) | Calin | 203 (93) | 45 (70)* | 5.71 (2.70–27.71) | 0.0001 | 93 | 30 | 1.32 (1.12–1.56) | 0.23 (0.13–0.43) |
| Insidious onset | Calin | 170 (80) | 48 (76) | 1.24 (0.63–2.41) | 0.534 | 80 | 24 | 1.05 (0.90–1.22) | 0.85 (0.51–1.42) |
↵* Denominator is not 220 for IBP or 66 for MBP due to missing responses. LR: likelihood ratio positive/negative.