Table 3. Patient Characteristics According to the Presence of CT-ILD Features.
| Characteristic | No ILD (n = 118) | Any ILD (n = 58) | p-value |
| Age, years | 58±8 | 61±9 | 0.071 |
| Male, n (%) | 43 (36) | 29 (50) | 0.085 |
| White, n (%) | 101 (86) | 51 (88) | 0.67 |
| Any college, n (%) | 87 (74) | 46 (79) | 0.42 |
| Ever smoking, n (%) | 62 (53) | 44 (76) | 0.003 |
| Current smoking, n (%) | 7 (6) | 14 (24) | <0.001 |
| Reported lung disease (n = 168), n (%) | 19 (17) | 8 (14) | 0.66 |
| RA duration, years | 8 (4–16) | 8 (5–19) | 0.22 |
| RF or CCP2 seropositivity, n (%) | 86 (73) | 52 (90) | 0.011 |
| RF seropositivity, n (%) | 71 (60) | 43 (75) | 0.047 |
| CCP2 seropositivity, n (%) | 73 (62) | 49 (86) | 0.001 |
| Any shared epitope alleles, n (%) | 80 (68) | 43 (75) | 0.34 |
| DAS28-CRP | 3.5 (2.8–4.3) | 3.8 (3.2–4.5) | 0.12 |
| CRP, mg/L | 2.3 (1.0–7.2) | 3.5 (1.2–9.3) | 0.58 |
| IL-6, pg/mL | 3.0 (1.6–7.0) | 4.5 (2.3–9.5) | 0.029 |
| Total SHS | 6 (0–26) | 12 (2–55) | 0.074 |
| Pain (100 mm VAS) | 19 (10–40) | 24 (8–47) | 0.52 |
| HAQ-DI (0–3) | 0.62 (0.12–1.25) | 0.75 (0.25–1.50) | 0.083 |
| Current prednisone, n (%) | 37 (31) | 30 (52) | 0.009 |
| Current non-biologic DMARDs, n (%) | 103 (88) | 47 (81) | 0.21 |
| Methotrexate, n (%) | 81 (69) | 33 (57) | 0.13 |
| Leflunomide, n (%) | 11 (9) | 8 (14) | 0.37 |
| Current biologic DMARDs, n (%) | 48 (41) | 34 (59) | 0.028 |
| TNF inhibitors, n (%) | 46 (39) | 33 (57) | 0.028 |
| Number of failed DMARDs | 1 (0–2) | 1 (0–2) | 0.80 |
| Any PFT Abnormality (n = 158), n (%) | 22 (21) | 22 (43) | 0.003 |
| Any PFT Restriction or Impaired Diffusion, n (%) | 12 (13) | 18 (41) | <0.001 |
| Any respiratory symptoms (n = 168), n (%) | 40 (36) | 29 (52) | 0.046 |
| Number of respiratory symptoms | 0 (0–1) | 1 (0–2) | 0.017 |
Values are mean ± standard deviation or median (interquartile range) unless otherwise noted.
RA = rheumatoid arthritis; RF = rheumatoid factor; CCP2 = 2nd generation anti-cyclic citrullinated peptide antibody; DAS = disease activity score; CRP = C-reactive protein; IL = interleukin; SHS = Total modified Sharp-van der Heijde Score; HAQ = Health Assessment Questionnaire Disability Index; TNF = tumor necrosis factor; DMARD = disease modifying anti-rheumatic drug; ILD = interstitial lung disease; PFT = pulmonary function testing; Impaired Diff = impaired diffusion.