Performance of power Doppler ultrasonography (PDUS) findings, classification criteria, other manifestations at baseline for predicting the final diagnosis of SpA in classified patients
| Characteristic | Se (95% CI) | Sp (95% CI) | LR+ (95% CI) | LR− (95% CI) | OR (95% CI) | p Value | c-index |
|---|---|---|---|---|---|---|---|
| PDUS finding | |||||||
| At least 1 enthesis involved | 86.2 (86.1 to 86.3) | 39.5 (39.5 to 39.6) | 1.4 (1.2 to 1.7) | 0.3 ( to 0.4 to 1.1) | 4.1 (1.5 to 11) | 0.003 | 0.63 |
| At least 1 vascularised enthesis | 76.5 (76.3 to 76.5) | 81.2 (81.1 to 8.4) | 4.1 (3.5 to 4.7) | 0.3 ( to 0.2 to 0.8) | 14.8 (5.3 to 37.2) | <0.0001 | 0.79 |
| Classification criteria set | |||||||
| Amor's | 60.8 (60.6 to 60.9) | 87.5 (87.3 to 87.6) | 4.8 (4 to 5.6) | 0.4 (0.1 to 0.8) | 10.8 (3.9 to 30.2) | <0.0001 | 0.74 |
| ESSG | 78.4 (78.3 to 78.5) | 62.5 (62.4 to 62.6) | 2 (1.7 to 2.4) | 0.3 ( to 0.2 to 0.9) | 6 (2.5 to 15.7) | <0.0001 | 0.70 |
| Berlin† | 68.4 (68.2 to 68.6) | 73.3 (73.1 to 73.5) | 2.6 (2.7 to 3.9) | 0.4 (0.1 to 0.8) | 6.5 (1.3 to 26.7) | <0.0001 | 0.70 |
| Axial ASAS* | 65.2 (65 to 65.4) | 80 (79.8 to 80.2) | 3.3 (2.3 to 4.3) | 0.4 ( to 0.2 to 1) | 8.3 (1.8 to 30.1) | 0.003 | 0.73 |
| Peripheral ASAS* | 50 (49.7 to 50.3) | 86.7 (86.4 to 87) | 3.8 (2.4 to 5.2) | 0.6 (0 to 1.2) | 6.3 (1 to 42.1) | 0.04 | 0.68 |
| Single manifestation† | |||||||
| IBP | 74.5 (74.4 to 74.6) | 45.8 (45.7 to 45.9) | 1.4 (1.1 to 1.7) | 0.6 (0 to 1.7) | 2.3 (1 to 5.7) | 0.03 | 0.60 |
| Arthritis | 31.4 (31.2 to 31.5) | 75 (75 to 75.2) | 1.2 (0.6 to 1.9) | 0.9 (0.7 to 1.2) | 1.3 (0.6 to 3.3) | NS | 0.53 |
| Enthesitis | 41.2 (41 to 41.3) | 66.7 (66.5 to 66.8) | 1.2 (0.7 to 1.8) | 0.9 (0.6 to 1.2) | 1.4 (0.6 to 3.2) | NS | 0.54 |
| Dactylitis | 7.8 (7.8 to 7.9) | 100 (99.7 to 100) | NA | 0.9 (0.8 to 1) | NA | NS | 0.54 |
| HLAB27+ AAU | 25.5 (25.4 to 25.6) | 89.6 (89.3 to 89.8) | 2.4 (1.5 to 3.4) | 0.8 (0.6 to 1) | 2.9 (0.1 to 9) | 0.05 | 0.57 |
| IBD | 7.8 (7.8 to 7.9) | 97.9 (97.6 to 98.2) | 3.8 (1.6 to 5.9) | 0.9 (0.8 to 1) | 4 (0.4 to 37.1) | 0.09 | 0.53 |
| Psoriasis | 33.3 (33.2 to 33.5) | 83.3 (83.1 to 83.6) | 2 (1.2 to 2.7) | 0.8 (0.6 to 1) | 2.5 (1 to 6.5) | 0.19 | 0.58 |
| HLA-B27+ | 62.7 (62.6 to 62.9) | 68.7 (68.6 to 68.9) | 2 (1.5 to 2.5) | 0.5 (0.1 to 0.9) | 3.7 (1.6 to 8.5) | 0.001 | 0.66 |
| NSAIDs response | 70.6 (70.5 to 70.7) | 54.1 (54 to 54.3) | 1.5 (1.2 to 1.9) | 0.5 (0 to 1) | 2.8 (1.2 to 6.5) | 0.008 | 0.62 |
| MRI positive findings | 36 (35.7 to 36) | 91 (90.9 to 91.4) | 4 (3.1 to 5) | 0.7 (0.5 to 0.9) | 5.8 (1.5 to 22.4) | 0.006 | 0.63 |
↵* Berlin and ASAS axial criteria were applied only to patients with IBP at baseline and who underwent pelvic MRI; ASAS peripheral criteria were applied only to patients for whom a diagnosis of arthritis, enthesitis or dactylitis was clinically confirmed at inclusion.
↵† Manifestations present and recorded at inclusion or retrieved from past medical history.
AAU, acute anterior uveitis; ASAS, Assessment of SpondyloArthritis International Society; AUC, area under the ROC curve; ESSG, European Spondylarthropathy Study Group; IBP, inflammatory back pain (including isolated buttock pain); IBD, inflammatory bowel disease; LR+, LR−, positive and negative likelihood ratios; NSAIDs, non-steroidal anti-inflammatory drugs, efficacy on axial complaints; Se, sensitivity; Sp, specificity.