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

Table 4 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	1.46	1.12–1.92	0.006
Time from symptom onset (per 1 day more)	0.99	0.98–1.02	0.823	0.99	0.97–1.01	0.408
African vs Italian origin	0.20	0.06–0.63	0.006	0.51	0.16–1.61	0.248
Asian vs Italian origin	0.28	0.12–0.63	0.002	0.68	0.30–1.54	0.354
Central/eastern Europe vs Italian origin	0.27	0.09–0.84	0.024	0.66	0.21–2.07	0.475
Latin American vs Italian origin	0.74	0.47–1.15	0.183	1.95	1.17–3.23	0.010
Obesity^b yes vs no	1.38	1.05–1.81	0.021	1.64	1.23–2.20	0.001
Moderate vs mild COVID-19^c	2.29	1.11–4.75	0.026	2.03	0.97–4.24	0.059
Severe vs nild COVID-19^c	3.98	1.92–8.29	0.0001	3.76	1.78–7.93	0.001
Critical vs mild COVID-19^c	7.56	3.70–15.46	< 0.0001	8.52	4.09–17.76	< 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