Table 2.
Multivariable analysis of predictors by cause-specific hazard model in the development cohort
| Variables | Severe exacerbation | COPD-specific readmission | ||||
| β | HR (95% CI) | P value | β | HR (95% CI) | P value | |
| BMI, kg/m2 | −0.043 | 0.96 (0.92 to 1.00) | 0.045 | −0.044 | 0.96 (0.92 to 1.00) | 0.044 |
| Education level, ref= ‘primary school and below’ | 0.429 | 1.54 (1.13 to 2.08) | 0.005 | 0.408 | 1.50 (1.11 to 2.04) | 0.009 |
| Smoking status, ref=‘never/former smoker’ | −0.344 | 0.71 (0.49 to 1.03) | 0.070 | −0.313 | 0.73 (0.50 to 1.07) | 0.100 |
| Ever diagnosed for COPD, ref=‘ever diagnosed’ | 0.533 | 1.70 (1.14 to 2.55) | 0.010 | 0.498 | 1.65 (1.10 to 2.47) | 0.016 |
| Frequency of hospitalisations for AECOPD in the past 12 months | 0.182 | 1.20 (1.06 to 1.35) | 0.003 | 0.185 | 1.20 (1.07 to 1.36) | 0.003 |
| Ever regularly treated with long-acting bronchodilators (consistent ≥3 months), ref= ‘yes’ | 0.521 | 1.68 (1.21 to 2.35) | 0.002 | 0.544 | 1.72 (1.23 to 2.41) | 0.001 |
| GOLD stages, ref=‘GOLD 1’ | ||||||
| GOLD 2 | 0.945 | 2.57 (0.97 to 6.80) | 0.057 | 0.927 | 2.53 (0.95 to 6.68) | 0.062 |
| GOLD 3 | 0.886 | 2.43 (0.93 to 6.35) | 0.071 | 0.850 | 2.34 (0.89 to 6.14) | 0.084 |
| GOLD 4 | 1.064 | 2.90 (1.08 to 7.78) | 0.035 | 1.047 | 2.85 (1.06 to 7.66) | 0.038 |
| Inhaled short-acting bronchodilators during hospitalisation, ref=‘yes’ | −0.456 | 0.63 (0.45 to 0.88) | 0.007 | −0.498 | 0.61 (0.43 to 0.85) | 0.003 |
| Methylxanthine treatment during hospitalisation, ref=‘yes’ | 0.848 | 2.33 (1.55 to 3.53) | 0.000 | 0.811 | 2.25 (1.49 to 3.40) | <0.001 |
| Expectorant treatment during hospitalisation, ref=‘yes’ | 0.251 | 1.29 (0.86 to 1.93) | 0.201 | 0.301 | 1.35 (0.90 to 2.03) | 0.132 |
| Chronic cor pulmonale, ref=‘yes’ | 0.395 | 1.48 (0.98 to 2.25) | 0.060 | 0.378 | 1.46 (0.95 to 2.24) | 0.078 |
| Diabetes×inhaled short-acting bronchodilators interaction | 0.743 | 2.10 (1.33 to 3.33) | 0.001 | 0.736 | 2.09 (1.31 to 3.33) | 0.002 |
| Chronic cor pulmonale×expectorant treatment interaction | 0.600 | 1.82 (0.93 to 3.55) | 0.073 | 0.616 | 1.85 (0.94 to 3.63) | 0.068 |
| Respiratory failure×oxygen therapy interaction | −0.649 | 0.52 (0.35 to 0.78) | 0.002 | −0.687 | 0.50 (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.