Table 1 SARA baseline characteristics
RA patients (n = 196) | Blood donors (n = 101) | p value | |
|---|---|---|---|
Characteristics | |||
Women, n (%) | 156/196 (80) | 54/101 (53) | < 0.001 |
Age, mean (range) | 63.9 (25–87) | 48.6 (20–74) | < 0.001 |
Disease duration years, mean (range) | 12.2 (0–57) | – | |
Erosions, n (%) | 109/193 (56) | – | |
Biologics, n (%) | 72/196 (37) | – | |
Glucocorticoids, n (%) | 52/196 (27) | – | |
Methotrexate, n (%) | 148/196 (76) | – | |
Other csDMARD, n (%) | 40/196 (20) | – | |
Risk factors | |||
Ever smoker, n (%) | 99/192 (52) | 34/99 (34) | 0.006 |
Current smoker, n (%) | 15/192 (8) | 10/99 (10) | 0.514 |
Never smoker, n (%) | 93/192 (48) | 65/99 (66) | 0.006 |
Cigarette pack-years, mean (SD) | 13.9 (13.8) | 8.3 (11.3) | 0.009 |
Shared epitope carriage, n (%) | 163/196 (83) | 47/101 (47) | < 0.001 |
No allele, n (%) | 34/196 (17) | 54/101 (54) | < 0.001 |
One allele, n (%) | 97/196 (50) | 33/101 (33) | 0.007 |
Two alleles, n (%) | 65/196 (33) | 14/101 (14) | < 0.001 |
Antibodies | |||
RF-positive, n (%) | 145/195 (74) | – | |
IgG ACPA | |||
Positive, n (%) | 157/196 (80) | 0/101 (0) | < 0.001 |
Level, median U/mL (SD) | 444.1 (923.8) | 0.1 (0.0) | < 0.001 |
IgA ACPA | |||
Positive, n (%) | 88/196 (45) | 0/101 (0) | < 0.001 |
Level, median AU/mL (SD) | 1.3 (151.9) | 1.3 (0.0) | < 0.001 |
Level total IgA in serum, median g/L (SD) | 2.5 (1.4) | 2.0 (0.7) | < 0.001 |
Level total IgA in saliva, median μg/mL (SD) | 61.5 (85.8) | 35.7 (24.7) | < 0.001 |