Table 2

Multivariable analysis of predictors by cause-specific hazard model in the development cohort

VariablesSevere exacerbationCOPD-specific readmission
βHR (95% CI)P valueβHR (95% CI)P value
BMI, kg/m2−0.0430.96 (0.92 to 1.00)0.045−0.0440.96 (0.92 to 1.00)0.044
Education level, ref= ‘primary school and below’0.4291.54 (1.13 to 2.08)0.0050.4081.50 (1.11 to 2.04)0.009
Smoking status, ref=‘never/former smoker’−0.3440.71 (0.49 to 1.03)0.070−0.3130.73 (0.50 to 1.07)0.100
Ever diagnosed for COPD, ref=‘ever diagnosed’0.5331.70 (1.14 to 2.55)0.0100.4981.65 (1.10 to 2.47)0.016
Frequency of hospitalisations for AECOPD in the past 12 months0.1821.20 (1.06 to 1.35)0.0030.1851.20 (1.07 to 1.36)0.003
Ever regularly treated with long-acting bronchodilators (consistent ≥3 months), ref= ‘yes’0.5211.68 (1.21 to 2.35)0.0020.5441.72 (1.23 to 2.41)0.001
GOLD stages, ref=‘GOLD 1’
 GOLD 20.9452.57 (0.97 to 6.80)0.0570.9272.53 (0.95 to 6.68)0.062
 GOLD 30.8862.43 (0.93 to 6.35)0.0710.8502.34 (0.89 to 6.14)0.084
 GOLD 41.0642.90 (1.08 to 7.78)0.0351.0472.85 (1.06 to 7.66)0.038
Inhaled short-acting bronchodilators during hospitalisation, ref=‘yes’−0.4560.63 (0.45 to 0.88)0.007−0.4980.61 (0.43 to 0.85)0.003
Methylxanthine treatment during hospitalisation, ref=‘yes’0.8482.33 (1.55 to 3.53)0.0000.8112.25 (1.49 to 3.40)<0.001
Expectorant treatment during hospitalisation, ref=‘yes’0.2511.29 (0.86 to 1.93)0.2010.3011.35 (0.90 to 2.03)0.132
Chronic cor pulmonale, ref=‘yes’0.3951.48 (0.98 to 2.25)0.0600.3781.46 (0.95 to 2.24)0.078
Diabetes×inhaled short-acting bronchodilators interaction0.7432.10 (1.33 to 3.33)0.0010.7362.09 (1.31 to 3.33)0.002
Chronic cor pulmonale×expectorant treatment interaction0.6001.82 (0.93 to 3.55)0.0730.6161.85 (0.94 to 3.63)0.068
Respiratory failure×oxygen therapy interaction−0.6490.52 (0.35 to 0.78)0.002−0.6870.50 (0.33 to 0.76)0.001
  • Diabetes×inhaled short-acting bronchodilators interaction: diabetes=‘yes’ and inhaled short-acting bronchodilators=‘yes’, then the interaction=‘yes’, else the interaction=‘no’. Chronic cor pulmonale×expectorant treatment interaction: chronic cor pulmonale=‘yes’ and expectorant treatment=‘yes’, then the interaction=‘yes’, else the interaction=‘no’. Respiratory failure×oxygen therapy interaction: respiratory failure=‘yes’ and oxygen therapy=‘yes’, then the interaction=‘yes’, else the interaction=‘no’.

  • .AECOPD, acute exacerbations of chronic obstructive pulmonary disease; BMI, body mass index; COPD, chronic obstructive pulmonary disease; GOLD, Global Initiative for Chronic Obstructive Lung Disease.