Associations of obstructive and restrictive lung disease: cross-sectional analysis at 15 years
| Obstructive lung disease | Restrictive lung disease | |||||||
|---|---|---|---|---|---|---|---|---|
| N | Normal | N | Obstructive N=30 | OR (95% CI) | N | Restrictive N=41 | OR (95% CI) | |
| Demographic characteristics | ||||||||
| Age, years | 303 | 60 (13) | 30 | 69 (10) | 1.06 (1.02 to 1.09) | 41 | 67 (13) | 1.04 (1.01 to 1.07) |
| Gender, female | 303 | 230 (76%) | 30 | 15 (50%) | 0.32 (0.15 to 0.68) | 41 | 17 (41%) | 0.22 (0.11 to 0.44) |
| BMI | 303 | 27.5 (4.9) | 30 | 28.0 (5.4) | 1.02 (0.94 to 1.10) | 41 | 29.2 (5.1) | 1.08 (1.00 to 1.16) |
| Smoking status | 303 | 30 | 41 | |||||
| Never | 112 (37%) | 2 (7%) | 1 | 13 (32%) | 1 | |||
| Past | 154 (51%) | 20 (67%) | 5.90 (1.32 to 26.4) | 19 (46%) | 0.68 (0.30 to 1.51) | |||
| Current | 37 (12%) | 8 (27%) | 15.91 (3.00 to 84.3) | 9 (22%) | 2.01 (0.74 to 5.50) | |||
| Clinical characteristics | ||||||||
| Swollen joint count, 28 joints | 303 | 0 (0–3) | 30 | 1 (0–3) | 1.05 (0.94 to 1.17) | 41 | 0 (0 to 3) | 1.01 (0.91 to 1.13) |
| Tender joint count, 28 joints | 303 | 2 (0–6) | 30 | 2 (0–10) | 1.05 (1.00 to 1.11) | 41 | 1 (0 to 7) | 1.04 (0.99 to 1.09) |
| DAS28CRP(3) | 237 | 2.97 (2.18–3.80) | 28 | 3.46 (2.32–4.43) | 1.49 (1.05 to 2.10) | 24 | 3.05 (2.43 to 3.67) | 1.22 (0.83 to 1.80) |
| HAQ | 302 | 0.75 (0.13–1.5) | 30 | 0.94 (0.38–1.88) | 1.60 (0.96 to 2.66) | 41 | 1.50 (0.88 to 2.0) | 2.90 (1.78 to 4.71) |
| CRP, mg/l | 237 | 8.5 (3.1–14.5) | 28 | 11.7 (6.3–20.5) | 1.01 (0.99 to 1.03) | 24 | 17.7 (6.5 to 24.7) | 1.01 (1.00 to 1.03) |
| RA, 1987 criteria | 303 | 236 (78%) | 30 | 24 (80%) | 1.00 (0.37 to 2.66) | 41 | 37 (90%) | 2.57 (0.85 to 7.78) |
| Nodules | 303 | 31 (10.2%) | 30 | 1 (3.3%) | 0.32 (0.04 to 2.51) | 41 | 8 (20%) | 2.22 (0.88 to 5.57) |
| Current Methotrexate use | 303 | 84 (28%) | 30 | 7 (23%) | 0.67 (0.27 to 1.68) | 41 | 6 (15%) | 0.42 (0.16 to 1.06) |
| Current oral steroids use | 303 | 23 (8%) | 30 | 6 (20%) | 2.23 (0.77 to 6.42) | 41 | 10 (24%) | 3.22 (1.30 to 7.98) |
| Respiratory symptoms | ||||||||
| Medication for respiratory symptoms | 303 | 32 (11%) | 30 | 8 (27%) | 3.68 (1.42 to 9.55) | 41 | 6 (15%) | 1.66 (0.61 to 4.52) |
| Breathlessness | 301 | 33 (11%) | 30 | 8 (27%) | 2.80 (1.09 to 7.20) | 41 | 9 (22%) | 2.28 (0.93 to 5.58) |
N=number of patients with available data. Values are mean (SD), median (IQR) for continuous variables or n (%) for categorical variables.
See Methods section for description of obstructive, restrictive and normal spirometry lung function test.
Bold type indicates statistical significance (p<0.05).
BMI, body mass index; CRP, C-reactive protein; DAS28, 28-joint Disease Activity Score; HAQ, Health Assessment Questionnaire; RA, rheumatoid arthritis; RLD, restrictive lung disease.