Table 3. Relationship between total serum bilirubin and outcomes in different models.

Outcomes	Non-adjusted, OR (95% CI)	Model 1, OR (95% CI)	Model 2, OR (95% CI)	Model 3, OR (95% CI)
30-day ICU mortality
TBIL per 1 mg/dL	1.04 (1.01, 1.06)*	1.07 (1.04, 1.11)*	1.07 (1.03, 1.11)*	1.04 (1.01, 1.08)*
TBIL category
<1.2 mg/dL	Reference	Reference	Reference	Reference
≥1.2, <2 mg/dL	1.14 (0.77, 1.70)	1.14 (0.77, 1.70)	1.13 (0.75, 1.69)	1.30 (0.85, 1.99)
≥2 mg/dL	1.45 (1.03, 2.03)*	1.64 (1.16, 2.32)*	1.51 (1.06, 2.15)*	1.51 (1.02, 2.22)*
In-hospital mortality
TBIL per 1 mg/dL	1.03 (1.01, 1.06)*	1.06 (1.03, 1.10)*	1.05 (1.02, 1.09)*	1.04 (1.01, 1.07)*
TBIL category
<1.2 mg/dL	Reference	Reference	Reference	Reference
≥1.2, <2 mg/dL	1.54 (1.12, 2.13)*	1.54 (1.11, 2.13)*	1.53 (1.10, 2.13)*	1.65 (1.17, 2.33)*
≥2 mg/dL	1.38 (1.03, 1.86)*	1.57 (1.16, 2.14)*	1.47 (1.07, 2.01)*	1.41 (1.01, 1.87)*

Model 1: adjusted for age and gender. Model 2: further adjusted for pneumonia, hypertension, COPD, renal failure, cancer, and diabetes mellitus. Model 3: further adjusted for admission type, SpO₂, PEEP, ALP, ALT, AST, serum glucose, and OASIS score. *P<0.05. OR, odds ratio; CI, confidence interval; ICU, intensive care unit; TBIL, total bilirubin; COPD, chronic obstructive pulmonary disease; SpO₂, pulse oxygen saturation; PEEP, positive end-expiratory pressure; ALP, alkaline phosphatase; ALT, alanine transaminase; AST, aspartate aminotransferase.