Table 1.
Baseline demographic and clinical characteristics of 37 patients with CTD-ILD receiving rituximab.
| Variable | Total n = 37 |
RA n = 19 |
SS n = 14 |
IM n = 4 |
p Value |
|---|---|---|---|---|---|
| Epidemiological characteristics | |||||
| Female sex, n (%) | 27 (73.0) | 13 (68.4) | 11 (78.6) | 3 (75.0) | 0.806 |
| Age in years, mean (SD) | 62.8 (9.9) | 67.7 (9.7) | 57.9 (7.9) | 56.6 (5.5) | 0.001 |
| Caucasian race, n (%) | 36 (97.3) | 19 (100.0) | 13 (92.9) | 4 (100.0) | 0.430 |
| Clinical–analytical characteristics | |||||
| Smoking | 0.147 | ||||
| Never smoked, n (%) | 20 (54.1) | 9 (47.4) | 7 (50.0) | 4 (100.0) | |
| Smoked at some stage, n (%) | 17 (45.9) | 10 (52.6) | 7 (50.0) | 0 (0.0) | |
| Duration of CTD, months, median (IQR) | 107.8 (49.5–188.8) | 151.0 (8.0–240.5) | 89.6 (51.3–184.4) | 35.1 (25.1–49.0) | 0.017 |
| Duration of ILD, months, median (IQR) | 65.4 (31.1–110.3) | 82.2 (37.4–120.1) | 64.5 (35.5–107.1) | 25.9 (25.0–36.0) | 0.136 |
| RF-positive (>10) n (%) | 19 (51.4) | 19 (100.0) | 0 (0.0) | 0 (0.0) | <0.001 |
| ACPA (<20), n (%) | 18 (48.6) | 18 (94.7) | 0 (0.0) | 0 (0.0) | <0.001 |
| ANA-positive, n (%) | 24 (64.9) | 6 (31.6) | 14 (100.0) | 4 (100.0) | <0.001 |
| Anti-scl70, n (%) | 7 (18.9) | 0 (0.0) | 7 (50.0) | 0 (0.0) | <0.001 |
| Anticentromere, n (%) | 3 (9.0) | 0 (0,0) | 3 (21,4) | 0 (0,0) | 0.156 |
| Anti-RNA polymerase 3, n (%) | 1 (2.7) | 0 (0.0) | 1 (7.1) | 0 (0.0) | 0.430 |
| Anti Ku, n (%) | 1 (2.7) | 0 (0.0) | 1 (7.1) | 0 (0.0) | 0.430 |
| Anti-PL7, n (%) | 2 (5.4) | 0 (0.0) | 0 (0.0) | 2 (50.0) | <0.001 |
| Anti-EJ, n (%) | 1 (2.7) | 0 (0.0) | 0 (0.0) | 1 (25.0) | 0.014 |
| Anti-TIF, n (%) | 1 (2.7) | 0 (0.0) | 0 (0.0) | 1 (25.0) | 0.014 |
| Treatment | |||||
| Time to initiation of rituximab *, median (IRQ) | 12.0 (6.5–48.2) | 25.1 (7.0–57.6) | 11.4 (3.9–43.6) | 7.4 (7.0–10.4) | 0.455 |
| Duration of treatment with rituximab, median (IQR) ** | 38.2 (23.4–69.9) | 45.3 (22.2–79.9) | 52.5 (24.7–63.3) | 22.8 (17.7–36.2) | 0.291 |
| Combined with csDMARDs, n (%) | 15 (40.5) | 9 (47.4) | 5 (35.7) | 1 (25.0) | 0.637 |
| Methotrexate, n (%) | 5 (13.5) | 2 (10.5) | 3 (21.4) | 0 (0.0) | 0.468 |
| Leflunomide, n (%) | 2 (5.4) | 2 (10.5) | 0 (0.0) | 0 (0.0) | 0.367 |
| Sulfasalazine, n (%) | 1 (2.7) | 1 (5.3) | 0 (0.0) | 0 (0.0) | 0.615 |
| Hydroxychloroquine, n (%) | 7 (18.9) | 4 (21.1) | 2 (14.3) | 1 (25.0) | 0.840 |
| Combination with immunosuppressants, n (%) | 20 (54.1) | 7 (36.8) | 9 (64.3) | 4 (100.0) | 0.044 |
| Mycophenolate, n (%) | 19 (51.4) | 6 (31.6) | 9 (64.3) | 4 (100.0) | 0.021 |
| Azathioprine, n (%) | 1 (2.7) | 1 (5.3) | 0 (0.0) | 0 (0.0) | 0.615 |
| Corticosteroids, n (%) | 25 (67.6) | 14 (73.7) | 7 (50.0) | 4 (100.0) | 0.121 |
| Doses of corticosteroids, median (IQR) | 5.0 (0.0–10.0) | 5.0 (0.0–10.0) | 2.5 (0.0–7.5) | 10.0 (8.1–10.5) | 0.519 |
Abbreviation: CTD: connective tissue disease; ILD: interstitial lung disease; RTX: rituximab; RA: rheumatoid arthritis; IM: inflammatory myopathy; SS: systemic sclerosis; RF: rheumatoid factor; ACPA: anticitrullinated peptide antibodies; ANA: antinuclear antibody; csDMARD: conventional synthetic disease-modifying antirheumatic drug; SD: standard deviation; IQR: interquartile range; * Time from diagnosis of ILD to initiation of rituximab ** Time from initiation of treatment with rituximab to end of follow-up or mortality. Statistical tests used: Pearson chi-squared (χ2), ANOVA, and Kruskal–Wallis.