Comparison of Two Waves of COVID-19 in Critically Ill Patients: A Retrospective Observational Study

Table 2

Comparison of risk factors for mortality.

Covariate	Overall		First wave		Second wave
	Adj. HR (95% CI)	-value	Adj. HR (95% CI)	-value	Adj. HR (95% CI)	-value
Patient characteristics
Age
<40 years	Reference		Reference		Reference
40–70 years	5.9 (1.85–18.51)	<0.01	8.3 (1.15–59.66)	0.04	2.5 (0.58–10.32)	0.22
>70 years	8.8 (2.79–27.99)	<0.01	10.37 (1.43–75.09)	0.02	5.5 (1.3–23.52)	0.02
African American race	0.7 (0.42–1.16)	0.18	0.7 (0.4–1.31)	0.3	0.7 (0.26–2.06)	0.56
Female sex	1.03 (0.8–1.32)	0.85	0.9 (0.68–1.35)	0.96	1.2 (0.78–1.76)	0.44
Acute kidney injury	2.4 (1.73–3.4)	<0.01	2.1 (1.3–3.27)	<0.01	2.4 (1.42–4.02)	<0.01
Past medical history
Chronic kidney disease	1.3 (0.95–1.81)	0.1	1.2 (0.76–1.96)	0.41	1.7 (1.02–2.68)	0.12
Diabetes	1 (0.78–1.3)	0.96	1.2 (0.83–1.64)	0.38	0.7 (0.48–1.1)	0.13
Hypertension	0.9 (0.7–1.28)	0.73	1 (0.7–1.56)	0.85	0.8 (0.5–1.26)	0.32
Cardiovascular disease	1 (0.79–1.36)	0.82	1.1 (0.74–1.56)	0.72	1 (0.65–1.56)	0.1
Treatment
Remdesivir	0.9 (0.61–1.2)	0.38	0.9 (0.54–1.38)	0.54	0.8 (0.47–1.44)	0.5
Dexamethasone	1.1 (0.82–1.57)	0.46	0.2 (0.02–1.04)	0.06	1.6 (0.73–3.67)	0.24
Convalescent plasma	0.7 (0.5–0.96)	0.03	0.6 (0.33–0.91)	0.02	0.8 (0.54–1.28)	0.4