Proportion of information in the total ultrasound score retained by the USRA9 score at baseline, assessed by linear regression R2
| Proportion of information in the total US score retained by the USRA9* score (R2) at baseline† | |||
|---|---|---|---|
| Modality | Side | Early RA (n=118) | Established RA (n=212) |
| GSUS | Unilateral‡ | 0.70 | 0.79 |
| Bilateral | 0.87 | 0.90 | |
| PDUS | Unilateral‡ | 0.75 | 0.83 |
| Bilateral | 0.90 | 0.92 | |
*Final US inflammation score (USRA9 score): MCP1, MCP2, MCP3, PIP2, PIP3, radiocarpal joint, extensor carpi ulnaris tendon, MTP2, MTP3.
†Linear regression analysis with the total US score at baseline as dependent variable and each individual joint/tendon score of the final joint set as independent variables.
‡Unilateral is dominant side.
GSUS, grey-scale ultrasound; MCP, metacarpophalangeal; MTP, metatarsophalangeal; PDUS, power Doppler ultrasound; PIP, proximal interphalangeal; RA, rheumatoid arthritis; US, ultrasound; USRA9, Ultrasound in Rheumatoid Arthritis 9 joint/tendon score.