Table 2.
Associations and difference in diagnostic accuracy between disc signal intensity and ‘LBP year’ at different thresholds and ages. Associations are expressed as odds ratios (OR) with 95% confidence intervals (95% CI) obtained from logistic regression analyses adjusted for body mass index. The probability of no difference in Area Under Curves (AUC) between Thresholds 1 and 2 is reported as p-values from chi square tests. More details are given in Additional File 4
| Disc signal intensity at 41 Years | Threshold 2: ≥ grade 2 (n = 356) (87.04%) OR (95% CI) |
Threshold 3: = grade 3 (n = 185) (45.23%) OR (95% CI) |
AUC comparison (p-value) |
|---|---|---|---|
| All participants (n = 409) | 2.02 (1.12;3.64)* | 2.57 (1.65;4.02)* | AUC T2 = AUC T3: 0.020* |
| Men (n = 197) | 2.88 (1.20;6.90)* | 2.52 (1.35;4.72)* | AUC T2 = AUC T3: 0.017* |
| Women (n = 210) | 1.63 (0.70;3.76) | 2.90 (1.50;5.60)* | AUC T2 = AUC T3: 0.016* |
| Upper lumbar spine (n = 409) | 1.16 (0.76;1.77) | 2.27 (0.91;5.62) | AUC T2 = AUC T3: 0.240 |
| Lower lumbar spine (n = 409) | 1.91 (1.16;3.16)* | 2.55 (1.61;4.05)* | AUC T2 = AUC T3: 0.111 |
| Disc signal intensity at 45 Years |
Threshold 2: ≥ grade 2 (n = 290) (85.04%) OR (95% CI) |
Threshold 3: = grade 3 (n = 170) (49.85%) OR (95% CI) |
AUC comparison (p-value) |
| All participants (n = 341) | 2.17 (1.18;4.00)* | 1.10 (0.69;1.75) | AUC T2 = AUC T3: 0.123 |
| Men (n = 160) | 2.25 (0.92;5.47) | 1.47 (0.75;2.90) | AUC T2 = AUC T3: 0.134 |
| Women (n = 181) | 2.11 (0.90;4.92) | 0.85 (0.45;1.61) | AUC T2 = AUC T3: 0.267 |
| Upper lumbar spine (n = 341) | 1.34 (0.84;2.14) | 1.48 (0.72;3.06) | AUC T2 = AUC T3: 0.767 |
| Lower lumbar spine (n = 341) | 1.57 (0.91;2.74) | 0.98 (0.61;1.55) | AUC T2 = AUC T3: 0.589 |
| Disc signal intensity at 49 Years |
Threshold 2: ≥ grade 2 (n = 251) (89.01%) OR (95% CI) |
Threshold 3: = grade 3 (n = 100) (35.46%) OR (95% CI) |
AUC comparison (p-value) |
| All participants (n = 282) | 2.65 (1.23;5.67)* | 1.49 (0.86;2.59) | AUC T2 = AUC T3: 0.859 |
| Men (n = 132) | 5.49 (1.63;18.52)* | 2.30 (1.05;5.06)* | AUC T2 = AUC T3: 0.825 |
| Women (n = 150) | 1.35 (0.43;4.25) | 0.98 (0.44;2.16) | AUC T2 = AUC T3: 0.01* |
| Upper lumbar spine (n = 282) | 2.08 (1.21;3.58)* | 5.08 (1.16;22.21)* | AUC T2 = AUC T3: 0.247 |
| Lower lumbar spine (n = 282) | 2.23 (1.15;4.30)* | 1.29 (0.74;2.26) | AUC T2 = AUC T3: 0.324 |
Note: The results for threshold ≥1 were underpowered and are therefore not presented in the Table
* P-value < 0.05