PCA analysis of clinical, serological, joint and tendon ultrasound variables
| Component | Clinical and serological variables |
|---|---|
| 1 | Swollen joints >6* , tender joints >6 |
| 2 | Age ≥60* |
| 3 | Early morning stiffness ≥60 min* |
| 4 | Swollen joint = 1*, Tender joint = 1 |
| 5 | ACPA positivity* |
| 6 | Abnormal CRP*, abnormal ESR |
| 7 | Gender* |
| Component | Joint and tendon ultrasound variables |
| 1 | MCP 1*, MCP 4, MCP 5, PIP 1, PIP 4 |
| 2 | Digit flexor tendon*, MCP 2, MCP 3, extensor carpi ulnaris tendon, wrist joint |
| 3 | PIP 2*, PIP 3, PIP 5 |
| 4 | MTP 2*, MTP 3, MTP 4 |
*Variables with the highest loading factor within each component.