Mortality among Italians and immigrants with COVID-19 hospitalised in Milan, Italy: data from the Luigi Sacco Hospital registry

Table 3 Cox regression analysis of the demographic and clinical factors associated with mortality due to SARS-CoV-2 infection

	HR	95% CI	p-value	AHR^a	95% CI	p-value
Age (per 1 year more)	1.05	1.04–1.06	< 0.0001	1.07	1.06–1.08	< 0.0001
Males vs females	1.17	0.90–1.50	0.234	1.41	1.08–1.85	0.011
Time from symptoms onset (per 1 day more)	1.00	0.98–1.02	0.823	0.99	0.97–1.01	0.464
Non Italians vs Italians	0.43	0.30–0.63	< 0.0001	1.04	0.70–1.55	0.831
Obesity^b YES vs NO	1.38	1.05–1.81	0.021	1.67	1.25–2.22	< 0.001
Moderate vs Mild COVID-19^c	2.29	1.11–4.75	0.026	2.05	0.98–4.27	0.056
Severe vs Mild COVID-19^c	3.98	1.92–8.29	< 0.001	3.84	1.82–8.09	< 0.001
Critically vs Mild COVID-19^c	7.56	3.70–15.46	< 0.0001	8.59	4.12–17.88	< 0.0001

HR hazard ratio, CI confidence interval
^aAdjusted for age, biological sex, time from symptoms onset, obesity and disease severity at hospital admission
^bObesity defined as body mass index of ≥ 30 points [17]
^cWHO disease severity classification [18]: mild = mild clinical symptoms, no imaging signs of pneumonia; moderate = fever, cough, dyspnea or other symptoms, imaging signs of pneumonia; severe = any of respiratory distress with a respiratory rate (RR) of ≥ 30 breaths per minute; resting oxygen saturation in air ≤ 93%; PaO₂ / FiO₂ ≤ 300 mmHg); critical = any of respiratory failure requiring mechanical ventilation; shock; any other organ failure needing intensive care