Table 2 Differences of exacerbation risk between pre- and post-BV period
|  | Number of patient with events (%) (n = 238) | Crude OR (95% CI) | Adjusted OR (95% CI) | |
|---|---|---|---|---|
pre-BV | post-BV | |||
COPD exacerbation | ||||
 Moderate | 127 (0.53) | 104 (0.44) | 0.678 (0.471–0.976) | 0.591 (0.383–0.914) |
 Severe | 91 (0.38) | 81 (0.34) | 0.833 (0.572–1.215) | 0.818 (0.545–1.230) |
 Moderate to Severe | 165 (0.69) | 141 (0.59) | 0.643 (0.440–0.941) | 0.571 (0.368–0.886) |