Table 1 Characteristics of the study population according to respective COVID-19 surge in France
All | First surge | Second surge | Third surge | p value | |
|---|---|---|---|---|---|
N = 105,979 | N = 25,150 | N = 32,689 | N = 48,140 | ||
Patient characteristics | |||||
Age | 67 (57–76) | 66 (56–76) | 70 (60–78) | 66 56–75) | < 0.001 |
Male sex | 67,951 (64.12%) | 16,662 (66.25%) | 21,304 (65.17%) | 29,985 (62.29%) | < 0.001 |
Charlson comorbidity index | |||||
0 | 69,886 (65.94%) | 14,596 (58.04%) | 20,321 (62.16%) | 34,969 (72.64%) | < 0.001 |
1–2 | 24,887 (23.48%) | 7180 (28.55%) | 8253 (25.25%) | 9454 (19.64%) | |
–4 | 6748 (6.37%) | 2039 (8.11%) | 2454 (7.51%) | 2255 (4.68%) | |
5 and more | 4458 (4.21%) | 1335 (5.31%) | 1661 (5.08%) | 1462 (3.04%) | |
Comorbidities | |||||
Arterial hypertension | 38,530 (36.36%) | 10,615 (42.21%) | 12,745 (38.99%) | 15,170 (31.51%) | < 0.001 |
Diabetes mellitus | 5151 (4.86%) | 1512 (6.01%) | 1919 (5.87%) | 1720 (3.57%) | < 0.001 |
Heart disease | 12,901 (12.17%) | 3713 (14.76%) | 4702 (14.38%) | 4486 (9.32%) | < 0.001 |
Lung disease | 10,732 (10.13%) | 3073 (12.22%) | 3589 (10.98%) | 4070 (8.45%) | < 0.001 |
Cirrhosis | 939 (0.89%) | 265 (1.05%) | 325 (0.99%) | 349 (0.72%) | < 0.001 |
Cancer | 2430 (2.29%) | 662 (2.63%) | 891 (2.73%) | 877 (1.82%) | < 0.001 |
Hematological malignancies | 1893 (1.79%) | 483 (1.92%) | 759 (2.32%) | 651 (1.35%) | < 0.001 |
Chronic kidney disease | 8756 (8.26%) | 2618 (10.41%) | 3312 (10.13%) | 2826 (5.87%) | < 0.001 |
Immunocompromised status | 5018 (4.73%) | 1743 (6.93%) | 2063 (6.31%) | 1212 (2.52%) | < 0.001 |
SAPS II score | 32 (24–41) | 32 (24–43) | 33 (26–42) | 32 (24–40) | < 0.001 |
Life support interventions | |||||
Maximal level of respiratory support | |||||
Invasive mechanical ventilation | 36,185 (34.14%) | 10,687 (42.49%) | 10,358 (31.69%) | 15,140 (31.45%) | < 0.001 |
Non-invasive mechanical ventilation | 6749 (6.37%) | 766 (3.05%) | 2190 (6.70%) | 3793 (7.88%) | |
High flow nasal canula therapy | 19,024 (17.95%) | 1743 (6.93%) | 6188 (18.93%) | 11,093 (23.04%) | |
Other oxygenotherapy | 44,021 (41.54%) | 11,954 (47.53%) | 13,953 (42.68%) | 18,114 (37.63%) | |
Median time between admission and tracheal intubation, in days (Q1–Q3) | 2 (0–5) | 1 (0–3) | 3 (1–6) | 2 (1–5) | < 0.001 |
Tracheostomy | 2297 (2.17%) | 896 (3.56%) | 632 (1.93%) | 769 (1.6%) | < 0.001 |
Prone position | 20,231 (19.09%) | 5808 (23.09%) | 5583 (17.08%) | 8840 (18.36%) | < 0.001 |
In patients with invasive mechanical ventilation only | 20,231 (55.91%) | 4879 (54.35%) | 5583 (53.90%) | 8840 (58.39%) | < 0.001 |
Extra-corporeal membrane oxygenation | 1125 (1.06%) | 344 (1.37%) | 297 (0.91%) | 484 (1.01%) | < 0.001 |
Vasopressors use | 28,943 (27.31%) | 9040 (35.94%) | 8453 (25.86%) | 11,450 (23.78%) | < 0.001 |
Renal replacement therapy | 7358 (6.94%) | 2320 (9.22%) | 2297 (7.03%) | 2741 (5.69%) | < 0.001 |
Clinical outcomes | |||||
Acute liver failure | 1806 (1.70%) | 530 (2.11%) | 563 (1.72%) | 713 (1.48%) | < 0.001 |
Disseminated intravascular coagulation | 446 (0.42%) | 121 (0.48%) | 143 (0.44%) | 182 (0.38%) | 0.1055 |
Pulmonary embolism | 7981 (7.53%) | 2146 (8.53%) | 2293 (7.01%) | 3542 (7.36%) | < 0.001 |
Venous thrombosis | 3969 (3.75%) | 1302 (5.18%) | 1100 (3.37%) | 1567 (3.26%) | < 0.001 |
ICU length of stay, days | 7 (3–16) | 8 (3–18) | 7 (3–15) | 7 (3–15) | < 0.001 |
Hospital length of stay, days | 14 (8–24) | 14 (7–26) | 14 (8–26) | 13 (8–23) | < 0.001 |