Table 5.
Risk of severe AECOPD events with cutoff values of CAI 50 and 100
| Cutoff value | Factors | RR | 95% CI | P-value |
|---|---|---|---|---|
| CAI 50 | CAI≤50 | 1 | ||
| CAI>50 | 1.612 | 1.065–2.440 | 0.024 | |
| Temperature (°C) | 0.989 | 0.979–0.999 | 0.034 | |
| Humidity (%) | 0.994 | 0.986–1.001 | 0.110 | |
| CAI 100 | CAI≤100 | 1 | ||
| CAI>100 | 1.025 | 0.736–1.429 | 0.882 | |
| Temperature (°C) | 0.989 | 0.979–0.999 | 0.033 | |
| Humidity (%) | 0.993 | 0.986–1.001 | 0.074 |
Abbreviations: AECOPD, acute exacerbations of chronic obstructive pulmonary disease; CAI, Comprehensive Air-quality Index; RR, adjusted relative risk.