Table 1 Baseline characteristics of the RA-risk cohort and SpA-risk cohort

Age, mean (SD)

54 (11)

28 (7)

Female sex, n (%)

71 (71)

25 (66)

Current smoker, n (%)

17 (17)

8 (21)

VAS joint pain, median (IQR)

24 (5–50)

–

Self-reported history of swollen joints (median, IQR)

0 (0–0)

–

RF positive, n (%)

72 (72)

–

ACPA positive, n (%)

37 (37)

–

High RA-risk (≥ 38% in 4 years)*, n (%)

40

-

Back pain present, n (%)

–

28 (74)

Inflammatory back pain present, n (%)

–

6 (21)

VAS back pain, median (IQR)

-

14 (0–36)

HLA-B27 positive, n (%)

–

20 (56)