RA-ILD cases, n = 84 | RA controls, n = 233 | P | |
---|---|---|---|
Years to index/matched date, median (IQR) | 1.5 (0.6–2.5) | 1.9 (1.6–5.6) | 0.84a |
Age, yrs, mean (SD) | 67 (10) | 66 (11) | 0.41a |
Female sex | 65 (77) | 186 (80) | 0.64a |
RA duration, yrs, mean (SD)b | 20 (12) | 20 (11) | 0.99a |
RF-positive | 73 (87) | 195 (84) | 0.48a |
CCP-positive | 70 (83) | 190 (82) | 0.71 |
White, non-Hispanic | 76 (90) | 219 (94) | 0.28 |
Education, below college | 30 (36) | 98 (42) | 0.31 |
Joint erosions | 49 (58) | 144 (62) | 0.58 |
Rheumatoid nodules | 42 (50) | 80 (34) | 0.01 |
BMI, kg/m2 | 0.18 | ||
< 20 | 4 (5) | 16 (7) | |
20 to < 25 | 20 (23) | 77 (33) | |
25 to < 30 | 32 (38) | 87 (37) | |
≥ 30 | 28 (33) | 53 (23) | |
Smoking status | 0.03 | ||
Never | 33 (39) | 124 (53) | |
Past | 43 (51) | 100 (43) | |
Current | 8 (10) | 9 (4) | |
Smoking, pack-yrs | < 0.001 | ||
Never smoker | 36 (43) | 126 (54) | |
1–9 | 7 (8) | 45 (19) | |
10–19 | 11 (13) | 28 (12) | |
20–29 | 7 (8) | 21 (9) | |
≥ 30 | 23 (27) | 13 (6) | |
CRP, mg/L | 0.006 | ||
Normal (< 3) | 33 (39) | 136 (58) | |
Low-positive (3 to < 10) | 31 (37) | 67 (29) | |
High-positive (≥ 10) | 20 (24) | 30 (13) | |
DAS28-CRP | < 0.001 | ||
Remission (< 2.6) | 27 (32) | 104 (45) | |
Low (2.6 to < 3.2) | 4 (5) | 39 (17) | |
Moderate (3.2 to < 5.1) | 37 (44) | 70 (30) | |
High (≥ 5.1) | 16 (19) | 20 (9) | |
MDHAQ Score | < 0.001 | ||
0 to < 0.2 | 15 (18) | 64 (27) | |
0.2 < 1.0 | 37 (44) | 127 (55) | |
≥ 1.0 | 32 (38) | 42 (18) | |
bDMARD use | 0.03 | ||
Never | 29 (35) | 76 (33) | |
Past | 19 (23) | 27 (12) | |
Current | 36 (43) | 130 (56) | |
Methotrexate use | 0.03 | ||
Never | 18 (21) | 24 (10) | |
Past | 32 (38) | 93 (40) | |
Current | 34 (41) | 116 (50) | |
Prednisone use | 0.007 | ||
Never | 5 (6) | 31 (13) | |
Past | 42 (50) | 140 (60) | |
Current | 37 (44) | 62 (27) |
Values are n (%) unless otherwise indicated.
↵a Matched factor.
↵b Range was 1–46 years for cases and 2–47 years for controls. Median (IQR) was 20 (10–31) for cases and 18 (11–29) for controls. bDMARD: biological disease-modifying antirheumatic drug; BRASS: Brigham Rheumatoid Arthritis Sequential Study; CCP: citrullinated peptide antibody; CRP: C-reactive protein; DAS28: Disease Activity Score in 28 joints; ILD: interstitial lung disease; MDHAQ: multidimensional Health Assessment Questionnaire; RA: rheumatoid arthritis; RF: rheumatoid factor.