Table 2.
Cross-sectional associations of demographic and RA-specific characteristics with high baseline %HAA
| Univariate model |
Multivariable model (extended) |
Multivariable model (reduced) |
||||
|---|---|---|---|---|---|---|
| OR (95% CI) | P-value | OR (95% CI) | P-value | OR (95% CI) | P-value | |
| Age per year | 1.003 (0.95, 1.05) | 0.91 | – | – | – | – |
| Female vs male | 2.44 (0.86, 6.92) | 0.094 | 4.25 (0.74, 24.57) | 0.106 | 5.34 (1.33, 21.43) | 0.018 |
| Caucasian vs other race | 0.74 (0.23, 2.38) | 0.62 | – | – | – | – |
| Ever smoker vs never smoker | 1.68 (0.66, 4.29) | 0.28 | – | – | – | – |
| Current smoking, yes vs no | 1.27 (0.34, 4.69) | 0.72 | – | – | – | – |
| Pack-years of smoking, per unit | 1.006 (0.99, 1.01) | 0.18 | 1.01 (0.99, 1.03) | 0.063 | 1.014 (1.003, 1.02) | 0.010 |
| BMI, per kg/m2 | 1.28 (1.16, 1.41) | <0.001 | 1.26 (1.09, 1.46) | 0.001 | 1.32 (1.17, 1.47) | <0.001 |
| Log RA duration, per year | 1.21 (0.74, 1.98) | 0.46 | – | – | – | – |
| RF or anti-CCP, yes vs no | 6.82 (0.89, 52.21) | 0.064 | – | – | – | – |
| Double RF and anti-CCP, yes vs no | 2.42 (0.86, 6.84) | 0.094 | – | – | – | – |
| RF, per unit | 1.001 (1.0001, 1.001) | 0.014 | – | – | – | – |
| RF titre above median value,a yes vs no | 4.24 (1.50, 11.96) | 0.006 | 3.01 (0.63, 14.41) | 0.168 | – | – |
| Anti-CCP, per unit | 1.006 (1.0003, 1.01) | 0.040 | – | – | – | – |
| Anti-CCP positive, yes vs no | 2.13 (0.60, 7.55) | 0.24 | – | – | – | – |
| Anti-CCP titre at the highest decile,b yes vs no | 4.18 (1.49, 11.68) | 0.006 | 8.49 (0.91, 79.19) | 0.060 | 11.34 (2.50, 51.22) | 0.002 |
| Any shared epitope vs none | 0.66 (0.27, 1.62) | 0.36 | – | – | – | – |
| 1 shared epitope allele vs none | 0.98 (0.39, 2.46) | 0.96 | 0.71 (0.17, 3.01) | 0.645 | – | – |
| 2 shared epitope alleles vs none | 0.13 (0.02, 1.04) | 0.054 | 0.11 (0.01, 1.54) | 0.101 | – | – |
| MUC5B minor allele vs none | 2.02 (0.63, 6.47) | 0.23 | – | – | – | – |
| 1 minor allele MUC5B vs none | 1.73 (0.49, 6.03) | 0.39 | 1.57 (0.32, 7.82) | 0.58 | – | – |
| 2 minor alleles MUC5B vs none | 6.06 (0.5, 73.4) | 0.157 | 1.19 (0.05, 28.98) | 0.914 | – | – |
| DAS28-CRP, per unit | 1.59 (1.06, 2.39) | 0.024 | – | – | – | – |
| DAS28-CRP >3.2, yes vs no | 4.33 (1.24, 15.10) | 0.022 | – | – | – | – |
| Log CDAI, per unit | 2.03 (0.79, 5.18) | 0.140 | 1.61 (0.28, 9.21) | 0.595 | – | – |
| CDAI >10 | 2.47 (0.31, 19.54) | 0.390 | – | – | – | – |
| Tender joints (44 joint count), per joint | 1.02 (0.98, 1.07) | 0.33 | – | – | – | – |
| Swollen joints (44 joint count), per joint | 1.09 (1.01, 1.19) | 0.028 | – | – | – | – |
| Log CRP, per mg/l | 1.61 (1.15, 2.27) | 0.006 | 0.99 (0.59, 1.67) | 0.967 | – | – |
| Log IL-6 level, per pg/ml | 1.44 (1.05, 1.96) | 0.023 | – | – | – | – |
| SHS, per unit | 0.99 (0.98, 1.01) | 0.58 | – | – | – | – |
| Use of non-biologic DMARDs, yes vs no | 1.27 (0.35, 4.57) | 0.72 | – | – | – | – |
| MTX, yes vs no | 0.89 (0.37, 2.18) | 0.80 | – | – | – | – |
| Cumulative dose of MTX (square root), per mg | 1.004 (0.99, 1.02) | 0.61 | – | – | – | – |
| Biologics, yes vs no | 1.30 (0.54, 3.12) | 0.55 | – | – | – | – |
| TNF inhibitors, yes vs no | 1.18 (0.49, 2.82) | 0.72 | – | – | – | – |
| Cumulative prednisone for the last 10 years | 0.98 (0.94, 1.04) | 0.59 | – | – | – | – |
| Baseline ILD score by expert read | 1.38 (1.13, 1.69) | 0.002 | ||||
| AUC | – | – | 0.87 (0.78, 0.97) | – | 0.88 (0.81, 0.95) | – |
OR represents the ratio of the likelihood of having high %HAA (affecting ≥10% of the lung parenchyma) vs not, per unit of the independent continuous variable of interest or for those with the independent dichotomous variable of interest vs those without.
a
Value is ≥100 units.
b
Value is ≥200 units. HAA: high attenuation areas; OR: odds ratio; MUC5B: mucin 5B; CDAI: Clinical Disease Activity Index; Log: logarithmic; SHS: Sharp–van der Heijde Score; AUC: area under the receiver operating characteristic curve; ILD: interstitial lung disease.