Table 1.

Comparison of baseline data between the three groups.

	Patients with COPD and pulmonary infection	Patients with COPD without pulmonary infection	Healthy controls	χ2	P
Sex
Male	40	43	47	0.328	>0.05
Female	38	35	31
Age (years)a	67.33 ± 6.11	67.74 ± 6.16	66.69 ± 6.60	0.552	0.577
Smoking
Yes	46	43	35	2.538	>0.05
No	32	35	39

^aMean  ±  standard deviation.

COPD, chronic obstructive pulmonary disease.