Baseline characteristics of each ACPA/erosions group
| ACPA negative | ACPA positive | |||
| Erosions negative n=701 | Erosions positive n=344 | Erosions negative n=1585 | Erosions positive n=1993 | |
| Female (%) | 83 | 83.4 | 81.4 | 84.9 |
| RF (% positive) | 31 | 33.5 | 93 | 95.3 |
| Smoking (%) | ||||
| Never | 81.2 | 88.6 | 85.3 | 91.6 |
| Current | 7.3 | 4.7 | 9.3 | 5.2 |
| Stopped | 11.6 | 6.7 | 5.4 | 3.2 |
| Age (years) mean (SD) | 51 (16) | 50 (14) | 48 (13) | 49 (12) |
| BMI mean (SD) | 27.7 (6.0) | 27.0 (6.0) | 25.9 (5.9) | 25.7 (5.7) |
| Symptom duration (months) median (IQR) | 12 (4; 36) | 36 (12; 72) | 18 (6; 48) | 48 (19; 108) |
| HAQ mean (SD) | 0.98 (0.61) | 1.1 (0.6) | 0.88 (0.59) | 1.1 (0.6) |
| DAS mean (SD) | 3.5 (0.93) | 4.0 (1.0) | 3.6 (0.97) | 4.0 (0.95) |
| ESR mean (SD) | 47.5 (32.8) | 60.1 (37.8) | 65.5 (36.0) | 72.8 (36.0) |
| Initial treatment (%) | ||||
| csDMARD mono | 51.8 | 42.2 | 55.5 | 29.1 |
| csDMARD combi | 14.3 | 17.4 | 17.9 | 22.6 |
| csDMARD+GC | 27.5 | 37.2 | 23.9 | 45.1 |
| Other | 6.43 | 3.2 | 2.7 | 3.2 |
| Country (%) | ||||
| Netherlands | 19.8 | 7.9 | 10.7 | 3.3 |
| India | 41.4 | 57.8 | 68.5 | 68.1 |
| Portugal | 9.2 | 7.3 | 4.6 | 2 |
| USA | 10.1 | 5.9 | 3 | 1 |
| Mexico | 7.5 | 6.2 | 1.3 | 1 |
| South-Africa | 1.1 | 2.7 | 2 | 21.4 |
| UK | 5.3 | 1.6 | 4.2 | 0.9 |
| Nigeria | 1.4 | 1.7 | 1.1 | 0.3 |
| Spain | 0.5 | 0.6 | 2 | 0.3 |
| Other | 3.7 | 8.3 | 2.7 | 1.7 |
Based on non-imputed data. Proportion of missing data per variable at baseline: gender 0.4%, RF 0.6%, smoking 3.8%, age 0.4%, BMI 56.8%, symptom duration 4.1%, HAQ 20.0%, DAS 24.9%, ESR 7.8%, initial treatment 0%.
ACPA, anti-citrullinated protein antibodies; BMI, body mass index; combi, combination therapy; csDMARD, conventional synthetic disease modifying anti-rheumatic drug; DAS, Disease Activity Score; ESR, erythrocyte sedimentation rate; GC, glucocorticoid; HAQ, Health Assessment Questionnaire; mono, monotherapy; RF, rheumatoid factor.