Table 4.

Number of acute exacerbation of COPD according to the clustering groups

Characteristics	ACO	Mild	Moderate	Severe	p-value
No	196	313	345	341
Follow-up duration, months	24 (12–36)	12 (6–24)	18 (6–30)	18 (12–36)	<0.001
Total number of AE	0.79±1.42	0.36±1.01	0.90±1.58	0.86±1.37	<0.001
Number of AE per year	0.29±0.49	0.18±0.51	0.32±0.49	0.39±0.58	<0.001

Note: Data are presented as mean±SD or median (interquartile range).

Abbreviations: AE, acute exacerbation; mo, month.