ICU strain and outcome in COVID-19 patients-A multicenter retrospective observational study.

To compare the characteristics, management, and prognosis of patients admitted to intensive care units (ICU) for coronavirus disease (COVID)-19 during the first two waves of the outbreak and to evaluate the relationship between ICU strain (ICU demand due to COVID-19 admissions) and mortality. In a multicentre retrospective study, 1166 COVID-19 patients admitted to five ICUs in France between 20 February and 31 December 2020 were included. Data were collected at each ICU from medical records. A Cox proportional-hazards model identified factors associated with 28-day mortality. 640 patients (55%) were admitted during the first wave (February to June 2020) and 526 (45%) during the second wave (July to December 2020). ICU strain was lower during the second wave (-0.81 [-1.04 --0.31] vs. 1.18 [-0.34-1.29] SD when compared to mean COVID-19 admission in each center during study period, P<0.001). Patients admitted during the second wave were older, had more profound hypoxemia and lower SOFA. High flow nasal cannula was more frequently used during the second wave (68% vs. 39%, P<0.001) and intubation was less frequent (46% vs. 69%, P<0.001). Neither 28-day mortality (30% vs. 26%, P = 0.12) nor hospital mortality (37% vs. 31%, P = 0.27) differed between first and second wave. Overweight and obesity were associated with lower 28-day mortality while older age, underlying chronic kidney disease, severity at ICU admission as assessed by SOFA score and ICU strain were associated with higher 28-day mortality. ICU strain was not associated with hospital mortality. The characteristics and the management of patients varied between the first and the second wave of the pandemic. Rather than the wave, ICU strain was independently associated with 28-day mortality, but not with hospital mortality.

Déclaration de conflit d'intérêts

A. Demoule reports grants, personal fees and non-financial support from Philips, personal fees from Baxter, personal fees and non-financial support from Fisher & Paykel, grants from French Ministry of Health, personal fees from Getinge, grants, personal fees and non-financial support from Respinor, grants, personal fees and non-financial support from Lungpacer, personal fees from Lowenstein, personal fees from Gilead, outside the submitted work. M. Fartoukh reports non-financial support from Biomerieux, personal fees from Pfizer outside the submitted work, and grants from French Ministry of Health. G. Louis reports other from Pfizer, other from Fresenius, outside the submitted work. E. Azoulay has received fees for lectures from Gilead, Pfizer, Baxter, and Alexion, and his research group has been supported by Ablynx, Fisher & Paykel, Jazz Pharma, and MSD. S. Nemlaghi has no conflict of interest to report. E. Jullien has no conflict of interest to report. C. Desnos has no conflict of interest to report. S. Clerc has no conflict of interest to report. E. Yvin has no conflict of interest to report. N. Mellati has no conflict of interest to report. C. Charron has no conflict of interest to report. G. Voiriot reports grants and personal fees from BioMérieux, grants from SOS Oxygène, grants from Janssen, outside the submitted work. Y. Picard has no conflict of interest to report. A. Vieillard-Baron reports research grant from GSK company. M. Darmon declares having received a grant from MSD, speaker fees from MSD, Astellas, and Gilead-Kite and having attended an advisory board for Gilead-Kite. This does not alter our adherence to PLOS ONE policies on sharing data and materials.