Table 1. Baseline characteristics of the participants and respiratory support at time of immunovirological profiling.
Values displayed are medians, with IQR in parentheses for continuous variables, or percentages for categorical variables. Percentages are rounded to the nearest unit. “Noncritical illness” includes hospitalized patients with no oxygen support (no O2) (moderate disease) and oxygen support on nasal cannula (NC) only (severe, but noncritical disease). “Critical illness” includes hospitalized patients on mechanical ventilation, either positive pressure noninvasive ventilation (NIV), endotracheal intubation (ETI), and extracorporeal membrane oxygenation (ECMO). ICU admission and intubation are different in all cohorts between noncritical and critical due to selection bias (at P < 0.05) in any of the patient characteristic. For continuous variables, statistical test: Mann-Whitney U test, unpaired t test. For categorical variables, χ2 test.
| Discovery cohort (n = 61) | Validation cohort (n = 87) | Confirmation cohort (n = 69) | |||||||
| Variable | Noncritical | Critical | Entire cohort | Noncritical | Critical | Entire cohort | Noncritical | Critical | Entire cohort |
| (n = 32) | (n = 29) | (n = 61) | (n = 68) | (n = 19) | (n = 87) | (n = 42 or 24)* | (n = 27 or 13)* | (n = 69 or 37)* | |
| Age | 63 (49–80) | 62 (51–68) | 62 (49–73)‡ | 75 (57–88) | 70 (55–73) | 71 (56–84)‡ | 56 (49–71)§ | 70 (57–79)§ | 63 (51–75) |
| Sex | |||||||||
| Male | 17 (53%) | 20 (69%) | 37 (61%) | 33 (49%) | 11 (58%) | 44 (51%) | 29 (69%) | 16 (59%) | 45 (65%) |
| Female | 15 (47%) | 9 (31%) | 24 (39%) | 35 (51%) | 8 (42%) | 43 (49%) | 13 (31%) | 11 (41%) | 24 (34%) |
| Days since symptom onset |
10 (8.5–13) | 11 (10–12) | 11 (9–12) | 10 (8–12) | 11 (9–12) | 10 (9–12) | 11 (10–12) | 11 (10–13) | 11 (10–13) |
| Days since hospital admission |
5.5 (3–7) | 5 (3–7) | 5 (3–7) | 4 (2–8) | 5 (3–8) | 5 (2–8) | 5.5 (3–8.5) | 5 (0–5) | 5 (3–7) |
| Respiratory support | |||||||||
| No O2 | 20 (62%) | 0 (0%) | 20 (33%)‡ | 48 (71%) | 0 (0%) | 48 (55%)‡ | 23 (55%) | 0 (0%) | 23 (33%) |
| NC | 12 (38%) | 0 (0%) | 12 (20%)‡ | 20 (29%) | 0 (0%) | 20 (23%)‡ | 19 (45%) | 0 (0%) | 19 (28%) |
| NIV | 0 (0%) | 7 (24%) | 7 (12%)‡ | 0 (0%) | 5 (26%) | 5 (6%)‡ | 0 (0%) | 15 (56%) | 15 (22%) |
| ETI | 0 (0%) | 20 (69%) | 20 (33%)‡ | 0 (0%) | 14 (74%) | 14 (16%)‡ | 0 (0%) | 12 (44%) | 12 (17%) |
| ECMO | 0 (0%) | 2 (7%) | 2 (3%)‡ | 0 (0%) | 0 (0%) | 0 (0%)‡ | 0 (0%) | 0 (0%) | 0 (0%) |
| Total metabolic risk factors (0–4) |
2 (1–3) | 2 (1–3) | 2 (1–3) | ||||||
| None | 3 (9%) | 6 (21%) | 9 (15%) | ||||||
| One or more | 29 (91%) | 23 (79%) | 52 (85%) | ||||||
| Overweight, yes† | 17 (53%) | 21 (72%) | 38 (62%) | ||||||
| Hypertension, yes | 20 (63%) | 15 (52%) | 35 (57%) | 42 (62%) | 13 (69%) | 55 (63%) | 9 (38%) | 9 (69%) | 18 (49%) |
| Dyslipidemia, yes | 13 (41%) | 11 (38%) | 24 (39%)‡ | 11 (16%) | 3 (16%) | 14 (16%)‡ | 7 (29%)§ | 11 (85%)§ | 18 (49%) |
| Diabetes, yes | 9 (28%) | 10 (35%) | 19 (31%)|| | 20 (29%) | 9 (47%) | 29 (33%) | 8 (33%)§ | 11 (85%)§ | 19 (51%)|| |
| Total chronic diseases (0–8) |
0 (0–1) | 0 (0–1) | 0 (0–1) | ||||||
| None | 22 (69%) | 17 (59%) | 39 (64%) | ||||||
| One or more | 10 (31%) | 12 (41%) | 22 (36%) | ||||||
| Chronic renal failure, yes |
4 (13%) | 6 (21%) | 10 (16%) | 9 (13%) | 2 (11%) | 11 (13%) | 3 (13%) | 3 (23%) | 6 (16%) |
| Chronic heart failure, yes |
2 (6%) | 2 (7%) | 4 (7%) | 12 (18%) | 2 (11%) | 14 (16%) | 2 (8%) | 0 (0%) | 2 (5%) |
| Chronic respiratory failure, yes |
3 (9%) | 5 (17%) | 8 (13%) | 6 (9%) | 5 (26%) | 11 (13%) | 5 (21%) | 0 (0%) | 5 (14%) |
| Chronic liver failure, yes |
0 (0%) | 0 (0%) | 0 (0%) | 2 (3%) | 0 (0%) | 2 (2%) | 0 (0%) | 0 (0%) | 0 (0%) |
| Organ transplant, yes | 2 (6%) | 2 (7%) | 4 (7%) | n/a | n/a | n/a | |||
| Immunosuppression, yes |
5 (16%) | 4 (14%) | 9 (15%)‡ | 2 (3%) | 2 (11%) | 4 (5%)‡ | 0 (0%)§ | 3 (25%)§ | 3 (8%) |
| Active cancer, yes | 1 (3%) | 3 (10%) | 4 (7%) | 9 (13%) | 4 (21%) | 13 (15%) | 3 (13%) | 0 (0%) | 3 (8%) |
| HIV, yes | 1 (3%) | 1 (3%) | 2 (3%) | 1 (2%) | 0 (0%) | 1 (1%) | n/a | n/a | n/a |
| Total risk factors (metabolic/organ, 0–12) |
2 (1–3) | 3 (1–4) | 2 (1–4) | ||||||
| None | 2 (6%) | 6 (21%) | 8 (13%) | ||||||
| One or more | 30 (94%) | 23 (79%) | 53 (87%) | ||||||
| ICU admission, yes | 3 (9%)§ | 27 (93%)§ | 30 (49%)‡ | 7 (10%)§ | 17 (90%)§ | 24 (28%)‡ | 2 (8%)§ | 12 (80%)§ | 14 (35%) |
| Intubation, yes | 2 (6%)§ | 22 (76%)§ | 24 (39%) | 7 (10%)§ | 17 (90%)§ | 24 (28%) | 1 (4%)§ | 9 (75%)§ | 10 (29%) |
| Duration of intubation (days) |
0 (0–0)§ | 20 (4–27)§ | 0 (0–18) | n/a | n/a | n/a | |||
| Duration of hospital stay (or in-hospital death) |
10.5 (6–16)§ | 26 (14–44)§ | 16 (9–30) | 14 (8–26.5)§ | 23 (19–48)§ | 18.5 (10–28) | 10.5 (7.5–14.5)§ |
21 (13–34)§ | 12 (8–27) |
| Outcome | |||||||||
| Death up to 60 days | |||||||||
| Alive | 30 (94%)§ | 18 (62%)§ | 48 (79%) | 61 (90%)§ | 14 (74%)§ | 75 (86%) | 42 (100%)§ | 16 (59%)§ | 58 (84%) |
| Dead | 2 (6%)§ | 11 (38%)§ | 13 (21%) | 7 (10%)§ | 5 (26%)§ | 12 (14%) | 0 (0%)§ | 11 (41%)§ | 11 (16%) |
*Only age, sex, and days since symptom onset variables have complete data in confirmation cohort; otherwise, the partial data are available for confirmation cohort.
†N_missing = 8 patients for discovery cohort.
‡Values are statistically different between discovery and validation cohorts.
§Values are statistically different between critical and noncritical groups.
||Values are statistically different between discovery and confirmation cohorts.