Table 1.
Baseline characteristics.
| Total | Carboxyhemoglobin | p-Value | ||
|---|---|---|---|---|
| Normal | Abnormal | |||
| n = 431 | n = 316 | n = 115 | ||
| Ages | 60.59 ± 15.77 | 60.19 ± 16.30 | 61.67 ± 14.24 | 0.39 |
| Sex (n, %) | ||||
| Female | 185 (42.92) | 138 (43.67) | 47 (40.87) | 0.66 |
| Male | 246 (57.08) | 178 (56.33) | 68 (59.13) | 0.66 |
| BMI | 32.38 ± 8.32 | 31.97 ± 8.10 | 33.51 ± 8.88 | 0.12 |
| Obesity | 206 (55.23) | 150 (54.55) | 56 (57.14) | 0.72 |
| Smoking status (n, %) | ||||
| Never | 252 (58.47) | 196 (62.03) | 56 (48.70) | 0.015 |
| Former | 130 (30.16) | 85 (26.90) | 45 (39.13) | 0.018 |
| Current | 24 (5.57) | 24 (7.59) | 0 (0.00) | <0.001 |
| Unknown | 25 (5.80) | 11 (3.48) | 14 (12.17) | 0.002 |
| Diabetes Mellitus | 50 (11.60) | 42 (13.29) | 8 (6.96) | 0.088 |
| Essential Hypertension | 68 (15.78) | 56 (17.72) | 12 (10.43) | 0.074 |
| Heart and other vascular disease | 36 (8.35) | 29 (9.18) | 7 (6.09) | 0.43 |
| Renal and electrolyte disorders | 124 (28.77) | 84 (26.58) | 40 (34.78) | 0.12 |
| Chronic pulmonary disease | 16 (3.71) | 13 (4.11) | 3 (2.61) | 0.58 |
| Pre-existing Anemias | 16 (3.71) | 8 (2.53) | 8 (6.96) | 0.043 |
| Intensive care unit/ Intermediate care unit |
215 (49.88) | 122 (38.61) | 93 (80.87) | <0.001 |
| Intubation and Mechanical Ventilation |
149 (34.57) | 69 (21.84) | 80 (69.57) | <0.001 |
Data are presented as mean ± SD for continuous variables and n (%) for categorical variables. Chi-square or Fisher’s exact test for categorical variables and t-test or Mann–Whitney test for continuous variables was used to compare patients between abnormal and normal carboxyhemoglobin level, as appropriate.