Association of carbon monoxide poisonings and carboxyhemoglobin levels with COVID-19 and clinical severity

Table 2 Analysis of patient survival, baseline values and variables (mean ± SD)

Survival			Outpatient (n = 258)	Hospitalization (n = 117)	ICU (n = 69)	Mortality (n = 35)	P value
Baseline characteristics
Age (yr)			50.27 ± 10.67	47.76 ± 11.05	61.61 ± 7.56		< 0.001
Gender		Female	107 (41.5)	47 (40.2)	21 (30.4)	12 (34.3)	0.1281
		Male	151 (58.5)	70 (59.8)	48 (69.6)	23 (65.7)
Exposure time (h)			3.90 ± 1.62	4.45 ± 1.68	5.19 ± 1.79	5.14 ± 1.78	< 0.001
COHb (%)			23.98 ± 4.19	3238 ± 2.81	38.49 ± 2.99	45.26 ± 3.19	< 0.001
Troponin I (ng/mL)			0.04 ± 0.09	0.33 ± 0.27	0.77 ± 0.21	1.35 ± 0.36	< 0.001
Lactate (mmol/L)			1.42 ± 0.39	3.54 ± 0.95	4.34 ± 0.68	8.14 ± 0.63	< 0.001
Patient groups	Pre-pandemic		198 (76.7)	40 (34.2)	10 (14.5)	5 (14.3)	< 0.0011
	Pandemic	Non-COVID-19	50 (19.4)	26 (22.2)	5 (7.2)	2 (5.7)
		Mild	8 (3.1)	28 (23.9)	21 (30.4)	3 (8.6)
		Moderate	2 (0.8)	16 (13.7)	17 (24.6)	10 (28.6)
		Severe	0	7 (6)	16 (23.2)	15 (42.9)

¹Chi-Square test.

Other P values were calculated by the Kruskal-Wallis H test. Bold values indicate significance at P < 0.05. SD: Standard deviation; COVID-19: Coronavirus disease 2019; ICU: Intensive care unit; COHb: Carboxyhemoglobin.