MSUS status in relation to the stages of RA development
| Non-active MSUS (n=177) | Active MSUS (n=96) | Univariable* OR (95% CI) | |
| 1. FDR without risk factors | 28 | 17 | 1.1 (0.6 to 2.2) |
| 2. Genetic risk factors (1 or 2 copies of SE) or systemic autoimmunity associated with RA (ACPA positivity), but without arthralgias or arthritis | 28 | 10 | 0.6 (0.3 to 1.3) |
| 3. Inflammatory arthralgias or self-reported symptoms associated with possible RA, but without clinical arthritis (some ACPA-positive)† | 90 | 42 | 0.7 (0.5 to 1.2) |
| 4. Unclassified arthritis (at least one swollen joint) (some ACPA-positive) | 31 | 27 | 1.8 (1.0 to 3.3)‡ |
The stages of RA development were defined as mutually exclusive for the purpose of this analysis. Active MSUS defined as a total B-mode score >8, including at least one joint with synovitis of grade 2 or 3, or Doppler score greater than 1.
*Univariable logistic regression analysis.
†Inflammatory arthralgias or self-reported symptoms associated with possible RA (Connective Tissue Disease Screening Questionnaire, CSQ >3).
‡P<0.05.
ACPA, anticitrullinated protein antibodies; FDR, first-degree relative; MSUS, musculoskeletal ultrasound; RA, rheumatoid arthritis; SE, shared epitope.