Demographic, clinical characteristics and spirometry values at 15 years
| Variable | N | |
|---|---|---|
| Demographic characteristics | ||
| Age, years | 421 | 62 (13) |
| Gender, female | 421 | 288 (68.4%) |
| Disease duration, years | 415 | 16.0 (1.1) |
| BMI | 421 | 27 (24–31) |
| Smoking status | 421 | |
| Never | 141 (33.5%) | |
| Past | 217 (51.5%) | |
| Current | 63 (15.0%) | |
| Clinical characteristics | ||
| Swollen joint count, 28-joint count | 421 | 0 (0–3) |
| Tender joint count, 28-joint count | 421 | 2 (0–6) |
| DAS28CRP(3) | 325 | 3.0 (2.2–3.9) |
| HAQ | 420 | 0.88 (0.25–1.63) |
| CRP, mg/l | 325 | 9.0 (3.6–17.0) |
| RF*, positive | 376 | 98 (26.1%) |
| ACPA*, positive | 323 | 74 (22.9%) |
| Shared epitope: | 392 | |
| 0 allele | 159 (40.6%) | |
| 1 allele | 170 (43.4%) | |
| 2 alleles | 63 (16.1%) | |
| RA, 1987 criteria | 421 | 334 (79.3%) |
| Nodules | 421 | 44 (10.5%) |
| Medication use | ||
| nbDMARD | 421 | 166 (39.4%) |
| Biologics | 421 | 26 (6.2%) |
| Oral steroids | 421 | 47 (11.2%) |
| Abnormal lung function test | ||
| FEV1 | 421 | 2.28 (0.70) |
| Men | 2.65 (0.77) | |
| Women | 2.10 (0.60) | |
| FVC | 421 | 2.86 (0.88) |
| Men | 3.39 (0.94) | |
| Women | 2.62 (0.73) | |
| Obstructive lung disease† | 333 | 30 (9.0%) |
| Men | 15 (17.1%) | |
| Women | 15 (6.1%) | |
| Restrictive lung disease† | 344 | 41 (11.9%) |
| Men | 24 (24.7%) | |
| Women | 17 (6.9%) | |
| Medication for respiratory symptoms | 421 | 52 (12.4%) |
| Breathlessness | 419 | 59 (14.1%) |
N=number of patients with available data. Values are mean (SD), median (IQR) for continuous variables or n (%) for categorical variables.
*Measured at baseline.
†Compared with patients with normal spirometry lung function test (see Methods section for description of obstructive, restrictive and normal spirometry lung function test).
ACPA, anti-citrullinated protein antibody; BMI, body mass index; CRP, C-reactive protein; DAS28, 28-joint Disease Activity Score; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; HAQ, Health Assessment Questionnaire; nbDMARD, non-biological disease-modifying antirheumatic drug; RA, rheumatoid arthritis; RF, rheumatoid factor.