Table 1. Comparisons of characteristics between Chinese patients and US patients with RA before and after matching.
| Characteristics | Before matched | After matched | ||||
|---|---|---|---|---|---|---|
| Chinese RA (n = 2,073) | US RA (n = 2,928) | P | Chinese RA (n = 1,660) | US RA (n = 1,660) | P | |
| Female*, n (%) | 1,629 (78.6) | 1,752 (59.4) [56.8– 61.9] | <0.001 | 1,223 (73.7) | 1,223 (73.7) [69.2–75.5] | 1.00 |
| Age*, years | 53.6 ± 12.9 | 57.9 (57.1, 58.6) | <0.001 | 55.9 ± 12.3 | 55.8 (52.0, 63.7) | 0.86 |
| Active smoking1, n (%) | 334 (16.1) | 1,614 (58.2) [55.3–61.0] | <0.001 | 321 (19.3) | 900 (59.5) [55.7–63.2] | <0.001 |
| RA disease duration, months | 45 (12, 114) | – | – | – | – | – |
| BMI2, kg/m2 | 21.9 ± 3.3 | 29.2 (25.0, 34.1) | <0.001 | 22.0 ± 3.2 | 29.6 (24.9, 34.9) | <0.001 |
| BMI categories, n (%) | <0.001 | <0.001 | ||||
| Underweight | 324 (15.6) | 32 (1.2) [0.7–1.9] | 251 (15.1) | 20 (1.4) [0.8–2.5] | ||
| Normal weight | 1,226 (59.1) | 595 (23.6) [21.4–25.9] | 981 (59.1) | 321 (23.7) [20.9–26.8] | ||
| Overweight | 435 (21.0) | 823 (29.4) [27.3–31.5] | 362 (21.8) | 435 (27.4) [24.6–30.4] | ||
| Obese | 88 (4.2) | 1,264 (45.9) [43.3–48.5] | 66 (4.0) | 778 (47.5) [44.0–51.1] | ||
| CRP3, mg/L | 6.0 (3.3, 23.0) | 5.1 (1.9, 15.7) | <0.001 | 6.6 (3.3, 25.3) | 4.0 (1.7, 10.8) | <0.001 |
| Comorbidity, n (%) | ||||||
| Malignancy | 118 (5.7) | 449 (16.2) [14.4–18.3] | <0.001 | 103 (6.2) | 209 (14.5) [12.2–17.2] | <0.001 |
| Hypertension4 | 593 (28.6) | 1,960 (61.2) [58.1–64.2] | <0.001 | 482 (29.0) | 999 (55.9) [52.0–59.7] | <0.001 |
| Diabetes5 | 253 (12.2) | 902 (24.0) [22.1–26.4] | <0.001 | 202 (12.2) | 446 (20.9) [18.4–23.6] | <0.001 |
| Dyslipidemia7 | 582 (28.1) | 2,178 (78.5) [76.3–80.7] | <0.001 | 459 (27.7) | 1,225 (77.7) [74.8–80.4] | <0.001 |
| Cardiovascular diseases6 | 194 (9.4) | 803 (24.2) [22.1–26.4] | <0.001 | 156 (9.4) | 370 (20.4) [18.0–23.0] | <0.001 |
| Previous medications | ||||||
| Glucocorticoids, n (%) | 1,029 (49.6) | 201 (7.6) [5.8–9.7] | <0.001 | 815 (49.1) | 119 (7.4) [5.6–9.5] | <0.001 |
| csDMARDs, n (%) | 1,455 (70.2) | 218 (8.7) [6.6–10.9] | <0.001 | 1,160 (69.9) | 122 (8.6) [6.3–10.8] | <0.001 |
| bDMADRs, n (%) | 142 (6.8) | 51 (2.0) [0.9–3.6] | <0.001 | 115 (6.9) | 28 (2.0) [1.0–3.5] | <0.001 |
| tsDMARDs, n (%) | 71 (3.4) | 1 (0.1) [0–0.2] | <0.001 | 58 (3.5) | 1 (0.1) [0–0.2] | <0.001 |
Notes:
Used for matching.
Active smoking was only available in 2,924 and 1,658 US RA patients before and after matching.
BMI was only available in 2,710 and 1,554 US RA patients before and after matching.
CRP was only available in 2,147 and 1,313 US RA patients before and after matching, and the normal range for CRP was less than 5.0 mg/L.
Hypertension was only available in 2,926 and 1,659 US RA patients before and after matching.
Diabetes was only available in 2,914 and 1,646 US RA patients before and after matching.
Cardiovascular diseases were only available in 2,927 and 1,660 US RA patients before and after matching.
Dyslipidemia was only available in 2,798 and 1,592 US RA patients before and after matching.
Data in Chinese RA patients are shown as number (percentage, %), mean ± SD, and median (IQL, 25th, 75th) if appropriate.
Data in US RA patients are shown as unweighted number (weighted percentage, %) [95% CI], weighted mean [95% CI] and weighted median (IQL, 25th, 75th) if appropriate.
RA, rheumatoid arthritis; BMI, body mass index; CRP, C-reactive protein; SD, standard deviation; IQL, interquartile limits. csDMARDs, conventional synthetic disease-modifying antirheumatic drugs; bDMADRs, biological disease-modifying antirheumatic drugs; tsDMARDs, targeted Synthetic Disease-Modifying Anti-Rheumatic Drugs.