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Table 2 Primary and secondary outcomes

From: Increased risk of severe COVID-19 in hospitalized patients with SARS-CoV-2 Alpha variant infection: a multicentre matched cohort study

  Exposed to historical lineages
N = 650
Exposed to VOC Alpha
N = 650
Crude measure of association (95% CI) Adjusted measure of association (95% CI)
WHO scale > 5 or non-rebreather mask at day 29
Number of events by Day 29 250 271   
Proportion of participants with an event at Day 29—% (95% CI) 38.5 (34.7–42.3) 41.7 (37.8–45.6) 1.15 (0.91–1.45) 1.33 (1.03–1.72)
Mortality rate at day 29
Number of deaths by Day 29 112 130   
Kaplan–Meier estimate of mortality by Day 29—% (95% CI) 19.0 (16.3–23.8) 24.0 (20.9–29.4) 1.18 (0.92–1.52) 1.21 (0.93–1.58)
WHO scale > 5 by day 29
Number of participants with WHO scale > 5 by Day 29 164 179   
Kaplan–Meier estimate of WHO scale > 5 by Day 29—% (95% CI) 20.5 (17.0–24.7) 26.2 (22.2–30.8) 1.19 (0.96–1.48) 1.24 (1.00–1.55)
Non-rebreather mask by day 29
Number of participants with non-rebreather mask by Day 29 177 208   
Kaplan–Meier estimate of non-rebreather mask by Day 29—% (95% CI) 29.7 (26.0–33.8) 35.2 (31.3–39.5) 1.18 (0.97–1.45) 1.20 (0.98–1.47)
High flow oxygen therapy by day 29*
Number of high flow oxygen therapy by Day 29 201 240   
Kaplan–Meier estimate of oxygen therapy by Day 29—% (95% CI) 35.4 (31.3–39.9) 42.1 (37.8–46.6) 1.20 (0.99–1.44) 1.18 (0.98–1.40)
ICU admission by day 29*
Number of ICU admission by Day 29 207 240   
Kaplan–Meier estimate of ICU admission by Day 29—% (95% CI) 36.0 (32.0–40.0) 41.7 (37.6–46.1) 1.15 (0.96–1.39) 1.12 (0.93–1.36)
Mechanical ventilation or ECMO by day 29*
Number of Mechanical ventilation or ECMO by Day 29 108 107   
Kaplan–Meier estimate of Mechanical ventilation or ECMO by Day 29—% (95% CI) 20.6 (17.0–24.7) 21.5 (17.4–25.7) 0.97 (0.74–1.27) 0.96 (0.73–1.27)
Hospitalization
Median time from symptoms onset to hospitalization (95% CI)—days 6 (5–6) 7 (6–7) 0.93 (0.83–1.04) 0.96 (0.86–1.08)
Median duration on hospitalization (95% CI)—days 11.5 (10–13) 11.0 (10–12) 1.02 (0.88–1.18) 0.95 (0.81–1.10)
Readmission
Number of readmissions after previous discharge 28 19   
Kaplan–Meier estimate of re-admission after a discharge—% (95% CI) 5.1 (3.4–7.7) 2.3 (1.2–4.3) 0.68 (0.38–1.23) (0.42–1.42)
  1. *In an analysis accounting for competing risk of death, the adjusted sHR were estimated as 1.17 (0.97–1.41), 1.09 (0.89–1.35) and 0.96 (0.73–1.25) respectively