Patient demographics, clinical and autoantibody status
| Cohort | All | COVID+ | COVID− | |
| N | 42 | 22 | 20 | |
| Age | Mean (CI) | 58.2 (62.7 to 54.1) | 60.9 (66.6 to 55.3) | 55.7 (62 to 48.7) |
| Sex | N male (%) | 29/42 (69) | 17/22 (77) | 12/20 (60) |
| Censored? | N (%) | 5/42 (12) | 4/22 (18) | 1/20 (5) |
| No of days before censoring | Mean (CI) | 39.4 (59.4 to 19.4) | 44.3 (66.2 to 22.3) | 20 (NA) |
| Days from symptom onset to ICU | Mean (CI) | 6 (8.3 to 3.7) | 7.5 (9.9 to 5.2) | 4.2 (8.5 to 0) |
| APACHE II on ICU admission | Mean (CI) | 25.3 (27.6 to 22.9) | 23.7 (27 to 20.4) | 27 (30.5 to 23.5) |
| Mean of SOFA score for first 3 days | Mean (CI) | 9.6 (10.7 to 8.5) | 9.3 (11 to 7.7) | 9.9 (11.6 to 8.3) |
| Mean of SOFA score for first 7 days | Mean (CI) | 8.9 (10.1 to 7.8) | 9.1 (11 to 7.3) | 8.7 (10.3 to 7.2) |
| ICU days (censored) | Mean (CI) | 14.1 (17.3 to 10.8) | 14.2 (20.5 to 7.8) | 14 (16.9 to 11.1) |
| Death in ICU | N (%) | 13/42 (31) | 7/22 (32) | 6/20 (30) |
| Mechanical ventilation days (censored) | Mean (CI) | 14.4 (18.9 to 10) | 16.8 (25.1 to 8.6) | 11.8 (14.9 to 8.7) |
| Total days of ventilation rescue measures | Mean (CI) | 2.9 (4.3 to 1.4) | 4.4 (7 to 1.8) | 1.2 (2 to 0.4) |
| Therapeutic anticoagulation used | N (%) | 8/42 (19) | 3/22 (14) | 5/20 (25) |
| Mean platelet count | Mean (CI) | 239 (269 to 209) | 264 (313 to 214) | 212 (245 to 179) |
| Mean platelet to neutrophil ratio | Mean (CI) | 35.2 (42 to 28.4) | 38.7 (48.4 to 29) | 31.4 (41.6 to 21.2) |
| aCL IgG | N (%) | 20/42 (48) | 13/22 (59) | 7/20 (35) |
| aCL IgM | N (%) | 9/42 (21) | 7/22 (32) | 2/20 (10) |
| Anti-β2GPI IgG | N (%) | 0 | 0 | 0 |
| Anti-β2GPI IgM | N (%) | 0 | 0 | 0 |
| Anti-domain 1 β2GP1 IgG | N (%) | 0 | 0 | 0 |
| Anti-PS/PT IgG | N (%) | 0 | 0 | 0 |
| Anti-PS/PT IgM | N (%) | 1/42 (2) | 1/22 (5) | 0 |
The data were censored on 31 May 2020. Days from symptom onset were self-reported by the patients or their representatives. The SOFA score was performed daily for all patients; the average was calculated for the first 3 and 7 days in the ICU for each patient, and the mean of those averages are reported. For patients who underwent tracheostomy, mechanical ventilation days are counted until successfully weaned from ventilatory support for 24 hours. Rescue measures included use of paralytics, proning and inhaled NO (counted additively if more than one intervention used in the same day). The clinical outcomes were measured for up to 3 months. All the serologies were tested longitudinally and are reported for the first 10 days from admission to the ICU (for standardisation among patients). There was no statistically significant difference between COVID+ and COVID− patients for all variables, using ANOVA for continuous variables and Fisher’s exact test for categorical variables at α=0.05, followed by the false discovery rate at q=0.05.
aCL, anticardiolipin; ANOVA, analysis of variance; APACHE, Acute Physiology and Chronic Health Evaluation (score); β2GP1, beta two glycoprotein I; ICU, intensive care unit; PS/PT, phosphatidyl serine/prothrombin complex; SOFA, sequential organ failure assessment (score).