Table 2. Comparisons of pH, PaO₂, and PaCO₂ in ACOS patients with different disease severity and healthy controls before and after treatment.

Group	pH			PaO2, mmHg			PaCO2, mmHg
	Before treatment	After treatment	P	Before treatment	After treatment	P	Before treatment	After treatment	P
Control	7.45 ± 0.05	7.46 ± 0.04	0.064	71.89 ± 7.19	70.70 ± 4.63	0.139	41.56 ± 3.59	41.01 ± 3.23	0.142
Mild ACOS	7.27 ± 0.04*	7.46 ± 0.03	< 0.001	65.38 ± 7.02*	70.04 ± 4.55	0.018	44.51 ± 6.50*	40.76 ± 3.83	0.007
Moderate ACOS	7.24 ± 0.03*	7.45 ± 0.02	< 0.001	59.06 ± 6.85*	71.01 ± 4.51	< 0.001	48.10 ± 5.16*	40.08 ± 3.17	< 0.001
Severe ACOS	7.21 ± 0.03*	7.37 ± 0.03†	< 0.001	53.06 ± 8.32*	64.74 ± 4.47†	< 0.001	52.62 ± 6.23*	45.71 ± 2.99†	< 0.001
Extremely severe ACOS	7.18 ± 0.02*	7.35 ± 0.02†	< 0.001	46.95 ± 13.81*	63.47 ± 12.98†	< 0.001	56.35 ± 5.37*	46.35 ± 4.08†	< 0.001

ACOS = asthma-chronic obstructive pulmonary disease overlap syndrome, PaO₂ = arterial oxygen partial pressure, PaCO₂ = partial pressure of carbon dioxide in artery.

^*P < 0.05, compared with the control group before treatment; ^†P < 0.05, compared with the control group after treatment.