Table 1 Baseline characteristics of the study population
N | All patients | < 65 yr | 65–74 yr | ≥ 75 yr | p |
|---|---|---|---|---|---|
1362 | 695 | 402 | 265 | ||
Age (yr) | 64 (54–72) | 54 (44–60) | 69 (67–72) | 79 (76–81) | < 0.001 |
Gender (female) (%) | 81.6 | 83.3 | 79.4 | 80.4 | 0.227 |
Disease duration (yr) | 4 (1–11) | 3 (0.8–9) | 6 (1.4–15) | 5 (1.2–15) | < 0.001 |
Stage (I + II) (%) | 68.2 | 76.0 | 61.7 | 57.8 | < 0.001 |
TNFi/ABA/TCZ (%) | 59.2/25.8/15.0 | 65.6/17.7/16.7 | 57/28.4/14.7 | 45.7/43.4/10.9 | < 0.001 |
Bio-naïve (%) | 74.1 | 75.4 | 71.9 | 74 | 0.442 |
MTX use (%) | 77.8 | 85.3 | 72.9 | 65.3 | < 0.001 |
  MTX dose (mg/w) | 14 (10–16) | 14 (10–16) | 12(10–16) | 12 (8–16) | < 0.001 |
GC use (%) | 21.2 | 17.3 | 24.4 | 26.8 | 0.001 |
  GC dose (mg/d) | 5 (2.5–7.5) | 4 (2.5–5) | 5 (2.5–9.3) | 5 (2.5–7.5) | 0.157 |
CRP (mg/dL) | 1.0 (0.2–3.0) | 0.6 (0.1–2.2) | 1.3 (0.3–3.2) | 1.5 (0.4–4.2) | < 0.001 |
ESR (mm/h) | 47 (24–75) | 35 (17–62) | 58 (32–80) | 66 (38–85) | < 0.001 |
RF (IU/mL) | 60 (18–167) | 45 (14–130) | 67 (23–188) | 105 (28–215) | < 0.001 |
ACPA positive (%) | 73.3 | 70.1 | 77.1 | 75.8 | 0.026 |
TJC, 0–28 | 7 (4–12) | 7 (3–12) | 7 (3–12) | 8 (4–13) | 0.062 |
SJC, 0–28 | 6 (3–10) | 6 (3–9) | 6 (3–10) | 7 (4–11) | 0.001 |
PGA, 0–100 (mm) | 52 (35–72) | 51 (32–71) | 51 (35–70) | 57 (42–76) | 0.002 |
EGA, 0–100 (mm) | 43 (29–58) | 40 (26–55) | 43 (30–57) | 49 (34–62) | < 0.001 |
CDAI | 24 (16–32) | 23 (15–31) | 24 (16–34) | 27 (20–35) | < 0.001 |
HAQ-DI | 1.3 (0.6–2.0) | 1 (0.4–1.6) | 1.3 (0.6–2) | 1.9 (1.3–2.5) | < 0.001 |
Pre-existing lung disease (%) | 27.4 | 18.4 | 32.3 | 43.4 | < 0.001 |