Predictive determinants of overall survival among re-infected COVID-19 patients using the elastic-net regularized Cox proportional hazards model: a machine-learning algorithm

Table 4 The hazard ratios (95% CIs) for time to in-hospital death in the re-infected COVID-19 patients using multiple regularized elastic-net Cox-adjusted PH regression

Features		HR (95% CI)	P-value	PH assumption test*
Type of patient transfer	Not-EMS	Reference	-	-
Type of patient transfer	EMS	3.90 (1.63-9.48)	0.002	0.782
SpO₂ (%)	>85	Reference	-	-
SpO₂ (%)	≤85	8.10 (2.97-22.00)	<0.001	0.132
WBC count (×10⁹ cells/L) for one unit increase		1.10 (1.03-1.15)	<0.001	0.895
Creatinine (mg/dL) for one unit increase		1.85 (1.48-2.30)	0.003	0.332

Note: The significant p-values (<0.05) are highlighted in bold
Abbreviations CI confidence interval, dof degree of freedom, EMS Emergency Medical Services, HR hazard ratio, SpO₂ saturation of peripheral oxygen, WBC white blood cell
*The p-value for testing the proportional hazards (PH) assumption based on the supremum test

ISSN: 1471-2458