Table 3.
Multivariate associations of pulmonary symptoms, cardiac findings, and patient characteristics with any PFT abnormality
| Characteristic | Model 1 (null) | Model 2 (complex) | Model 3a (simplified) | P value | |||
|---|---|---|---|---|---|---|---|
| OR | 95% CI | OR | 95% CI | OR | 95% CI | ||
| Frequent cough | 1.61 | (0.49 to 5.25) | 2.05 | (0.41 to 10.3) | |||
| Chronic phlegm | 2.64 | (0.87 to 8.02) | 3.01 | (0.56 to 16.3) | 4.16 | (1.21 to 14.4) | 0.02 |
| Frequent wheezing | 2.84 | (0.74 to 10.9) | 2.12 | (0.37 to 12.1) | |||
| Breathlessness at 100 yards | 2.24 | (0.60 to 8.32) | 11.2 | (1.54 to 81.6) | 5.96 | (1.25 to 28.3) | 0.03 |
| Reported diagnosis of pulmonary disease | 4.57 | (1.35 to 15.4) | 3.77 | (1.42 to 10.0) | 0.01 | ||
| CAC >100 | 1.25 | (0.38 to 4.11) | |||||
| Age, per year | 1.04 | (0.97 to 1.12) | |||||
| Male vs. female | 0.87 | (0.27 to 2.84) | |||||
| White vs. other race | 0.69 | (0.20 to 2.31) | |||||
| Reported exercise, per quartile | 0.95 | (0.57 to 1.57) | |||||
| BMI, per kg/m2 | 0.91 | (0.82 to 1.00) | 0.93 | (0.85 to 1.01) | 0.08 | ||
| Current smoking | 5.34 | (1.12 to 25.4) | 4.01 | (1.22 to 13.3) | 0.02 | ||
| Ever smoking vs. never smoking | 0.73 | (0.23 to 2.31) | |||||
| RA duration, per year | 1.01 | (0.95 to 1.07) | |||||
| RF seropositivity | 1.53 | (0.44 to 5.29) | |||||
| Anti-CCP seropositivity | 2.99 | (0.69 to 12.9) | 2.82 | (0.96 to 8.29) | 0.06 | ||
| DAS28, per unit | 0.78 | (0.45 to 1.33) | |||||
| HAQ, per unit | 0.86 | (0.35 to 2.10) | |||||
| Log-modified Sharp score, per log unit | 1.16 | (0.71 to 1.91) | |||||
| Current prednisone use | 2.54 | (0.95 to 6.85) | 2.65 | (1.12 to 6.25) | 0.03 | ||
| Current nonbiologic use | 0.38 | (0.08 to 1.88) | |||||
| Current biologic use | 0.82 | (0.27 to 2.52) | |||||
Model 1 (null), pulmonary symptoms only; Model 2 (complex), multivariable model with extended covariate list; Model 3, multivariate model with covariates reduced based on hierarchical modeling. BMI, body mass index; CAC, coronary artery calcium; CCP, cyclic citrullinated peptide; CI, confidence interval; DAS28, RA Disease Activity Score in 28 joints; HAQ, Health Assessment Questionnaire; OR, odds ratio; PFT, pulmonary function test; RA, rheumatoid arthritis; RF, rheumatoid factor. aP value for the likelihood ratio test comparing Models 2 and 3 = 0.801, indicating that the simpler model was not statistically different in predicting the variance in the outcome than the more complex model.