Table 3.

Prognostic factors for patients with idiopathic pulmonary fibrosis (IPF) and connective tissue disease-associated interstitial lung disease (CTD-ILD) using univariate Cox regression analysis. Immunosuppressants include prednisone, azathioprine, cyclophosphamide, and mycophenolate mofetil.

A. IPF and CTD-ILD population
VariableN UsedpHazard RatioLCLUCL
GERD: gastroesophageal reflux disease; RF: rheumatoid factor; DLCO: diffusion capacity for carbon monoxide; FVC: forced vital capacity; FEV1: forced expiratory volume in 1 second; NYHA: New York Heart Association; O2 exercise: oxygen saturation with exercise; LCL: lower confidence limit; UCL: upper confidence limit.
CTD vs IPF1840.0830.5710.3041.075
Age at diagnosis1820.00011.0421.0211.064
ILD disease duration1840.0751.2040.9811.479
Sex (women)1840.0620.6310.3891.023
Ethnicity (white)1730.0671.7250.9623.093
Anemia1200.0033.0031.4716.131
GERD1800.0210.5170.2960.904
Raynaud’s1760.0030.1590.0480.525
RF-positive530.0412.9251.0478.171
DLCO174< 0.00010.9650.9390.974
FVC1780.0010.9770.9650.990
FEV11730.0020.9820.9710.994
NYHA class143< 0.00012.4971.7503.563
O2 exercise830.0060.9110.8520.974
O2 sat ever < 90%1760.2321.4050.8042.455
Immunosuppressants1840.0032.4481.3514.436
B. CTD-ILD population only
VariableN UsedpHazard RatioLCLUCL
SSc vs non-SSc620.0140.1470.0320.673
Age at diagnosis610.0691.0470.9961.100
ILD disease duration620.9630.9920.6941.416
Sex (women)620.6401.4310.3196.429
Ethnicity (white)600.7881.1770.3583.867
ANA-positive420.0100.0510.0050.486
Raynaud’s620.0040.1040.0220.492
DLCO570.0190.9530.9160.992
FVC590.0770.9770.9531.002
O2 sat ever < 90%580.6940.6580.0825.269
Immunosuppressants620.0434.7881.05221.799
  • SSc: systemic sclerosis-associated ILD; non-SSc: nonsystemic sclerosis CTD-associated ILD; ANA-positive: antinuclear antibody ≥ 1:80; DLCO: diffusion capacity for carbon monoxide; FVC: forced vital capacity; LCL: lower confidence limit; UCL: upper confidence limit; O2 sat: oxygen saturation.