Table 2.

Association of COHb levels with smoking and outcomes.

Variable	Mean ± SD COHb (%)	P value
Active smoking
Yes (n = 185)/no (n = 111)	3.16 ± 2.38/1.61 ± 0.52	<0.001
Treatment with invasive mechanical ventilation during the current hospitalization
Yes (n = 49)/no (n = 251)	2.01 ± 1.42/2.19 ± 1.68	0.49
In-hospital mortality
Yes (n = 33)/no (n = 267)	1.85 ± 0.75/2.20 ± 1.72	0.25
90 days rehospitalization
Yes (n = 123)/no (n = 177)	1.96 ± 1.16/2.30 ± 1.90	0.08
6 months rehospitalization
Yes (n = 149)/no (n = 151)	2.07 ± 1.32/2.24 ± 1.90	0.36
1 year rehospitalization
Yes (n = 179)/no (n = 121)	2.05 ± 1.28/2.31 ± 2.06	0.18

Data are expressed as means ± SD or numbers of presented cases. COHb, carboxyhemoglobin.