Table 5– Prospective cohort: acute exacerbations, univariate analysis of variables at the time of diagnosis
VariableHazard ratio (95% CI)p-value
Age at diagnosis yrs1.02 (0.96–1.10)ns
Smoking pack-yrs0.99 (0.95–1.03)ns
Time to diagnosis months1.01 (0.98–1.04)ns
BMI m·kg−20.92 (0.79–1.07)ns
MRC dyspnoea score1.96 (1.18–3.30)0.0095
6MWD m1.00 (1.00–1.00)ns
6MWD % pred0.98 (0.96–1.00)ns
Desaturation at 6MWT#0.43(0.10–0.97)0.040
PA–a,O2 mmHg1.03(1.00–1.07)0.053
FVC % pred0.98 (0.95–1.01)ns
DL,CO % pred0.94 (0.90–0.98)0.0007
CPI1.05 (1.01–1.10)0.022
HRCT fibrosis score % of total lung volume1.05 (1.00–1.10)0.063
BAL total cell count cells·mL−11.00 (1.00–1.00)ns
Concomitant emphysema3.37 (1.12–11.17)0.030
  • BMI: body mass index; MRC: Medical Research Council; 6MWD: 6-min walking distance; % pred: % predicted; 6MWT: 6-min walking test; PA–a,O2: alveolar–arterial oxygen tension difference; FVC: forced vital capacity; DL,CO: diffusing capacity of the lung for carbon monoxide; CPI: composite physiologic index; HRCT: high-resolution computed tomography; BAL: bronchoalveolar lavage; ns: not significant. #: no desaturation (arterial oxygen saturation ≤88%) during the 6MWT.