Table 2.
Pulmonary evaluation results
| Variable | Autoantibody Positive Cases (N=42) |
Autoantibody Negative Controls (N=15) |
P- value+ |
Early RA (N=12) |
P- value++ |
|---|---|---|---|---|---|
| Spirometry* | |||||
| FEV1/FVC ratio <70% predicted | 5 (12%) | 0 (0%) | 0.311 | 4 (33%) | 0.098 |
| Forced expiratory flow (25–75) <70% predicted | 13 (31%) | 2 (13%) | 0.187 | 6 (50%) | 0.307 |
| High-resolution computed tomography (HRCT) | |||||
| Any Airways Disease (all subjects)** | 32 (76%) | 5 (33%) | 0.005 | 11 (92%) | 0.421 |
| Bronchial wall thickening | 21 (50%) | 2 (13%) | 0.015 | 10 (83%) | 0.041 |
| Bronchiectasis | 6 (14%) | 1 (7%) | 0.662 | 2 (17%) | 1.000 |
| Centrilobular opacities | 10 (24%) | 1 (7%) | 0.256 | 6 (50%) | 0.148 |
| Air trapping | 29 (69%) | 1 (7%) | 0.000 | 10 (83%) | 0.474 |
| Airways disease, never smokers | 19/26 (73%) | 4/12 (33%) | 0.033 | 6/7 (86%) | 0.652 |
| Airways disease, no history of lung disease*** | 22/31 (71 %) | 5/14 (36%) | 0.047 | 5/6 (83%) | 1.000 |
| Airways disease, Denver participants only | 22/31 (71 %) | 5/15 (33%) | 0.025 | 11/12 (92%) | 0.237 |
| Airways disease, no joint tenderness | 26/34 (76%) | 5/13 (38%) | 0.020 | - | - |
| Parenchymal disease**** | 4 (10%) | 1 (7%) | 1.000 | 5 (42%) | 0.019 |
| Nodules | 4 (10%) | 0 (0%) | 0.564 | 3 (25%) | 0.175 |
| Alveolar infiltrates (ground glass opacities) | 0 (0%) | 1 (7%) | 0.263 | 2 (17%) | 0.046 |
| Lung fibrosis | 0 (0%) | 0 (0%) | 1.000 | 0 (0%) | 1.000 |
|
Spirometry in subjects with airways disease identified by HRCT* |
|||||
| FEV1/FVC ratio <70% predicted | 4/32(13%) | 0/5 (0%) | - | 4/11 (36%) | - |
| Forced expiratory flow (25–75) <70% predicted | 12/32 (38%) | 0/5 (0%) | - | 6/11 (55%) | - |
Predictive values calculated according to the 3rd National Health and Nutritional Examination Survey (NHANES III)(Hankinson JL et al, Am J Resp Crit Care Med 1999); Obstructive disease = FEV1/FVC <70% of predicted; Reduced Forced Expiratory Flow (25–75) may be more sensitive for airways disease and obstruction than FEV1/FVC measurements (Ciprandi G et al, Am J Rhin 2006).
Airways disease included bronchial thickening, bronchiectasis, air trapping or centrilobular nodularity (these latter findings indicating small airways disease/inflammation); parenchymal disease = alveolar infiltrates (ground glass appearance on HRCT) and parenchymal nodules. Of note, air trapping results when small airways disease results in obstruction of airway outflow and subsequent overdistension of the alveoli on expiration which is seen on HRCT imaging as increased air density.
Chronic lung disease as assessed at the time of the lung study visit by questionnaire and including emphysema, asthma, chronic bronchitis as diagnosed by a health-care provider.
Parenchymal disease included ground-glass opacities, parenchymal nodules and lung fibrosis.
P-value comparing autoantibody positive cases to autoantibody negative controls.
P-value comparing autoantibody positive cases to Early RA.