Comparison of Patients Infected With Delta Versus Omicron COVID-19 Variants Presenting to Paris Emergency Departments : A Retrospective Cohort Study

Donia Bouzid; Benoit Visseaux; Christian Kassasseya; Asma Daoud; Florent Fémy; Christelle Hermand; Jennifer Truchot; Sebastien Beaune; Nicolas Javaud; Olivier Peyrony; Anthony Chauvin; Prabakar Vaittinada Ayar; Arthur Bourg; Bruno Riou; Stephane Marot; Ben Bloom; Marine Cachanado; Tabassome Simon; Yonathan Freund; IMProving Emergency Care (IMPEC) FHU Collaborators Group

doi:10.7326/M22-0308

Comparison of Patients Infected With Delta Versus Omicron COVID-19 Variants Presenting to Paris Emergency Departments : A Retrospective Cohort Study

Ann Intern Med. 2022 Jun;175(6):831-837. doi: 10.7326/M22-0308. Epub 2022 Mar 15.

Authors

Donia Bouzid¹, Benoit Visseaux², Christian Kassasseya³, Asma Daoud⁴, Florent Fémy⁵, Christelle Hermand⁶, Jennifer Truchot⁷, Sebastien Beaune⁸, Nicolas Javaud⁹, Olivier Peyrony¹⁰, Anthony Chauvin¹¹, Prabakar Vaittinada Ayar¹², Arthur Bourg¹³, Bruno Riou¹⁴, Stephane Marot¹⁵, Ben Bloom¹⁶, Marine Cachanado¹⁷, Tabassome Simon¹⁸, Yonathan Freund¹⁴; IMProving Emergency Care (IMPEC) FHU Collaborators Group

Collaborators

IMProving Emergency Care (IMPEC) FHU Collaborators Group:
Maud Salmona, Jérôme Le Goff, David Veyer, Richard Chocron, Clément Augustin, Flore Rozenberg, Jean-François Meritet, Aurélie Schnuriger, Slim Fourati, Mehdi Khellaf, Audrey Coulomb, Frédéric Gindre, Khouloud Aloui, Hervé Jacquier, Xavier Eyer, Christophe Choquet, Vittiaroat Ing, Thomas Pavlovsky, Nadhira Houhou-Fidouh, Valentine Ferré, Luce Landraud, Hélène Goulet, Youri Yordanov, Laurence Berard, Alexandra Rousseau, Théophile Morel, Theophile Vieux, Simon Cahen, Melkir Saib

Affiliations

¹ Emergency Department, Hôpital Bichat, Assistance Publique - Hôpitaux de Paris, and Université Paris Cité, IAME (Infection, Antimicrobial, Modelisation, Evolution), Inserm, Paris, France (D.B.).
² Virology Department, Hôpital Bichat, Assistance Publique - Hôpitaux de Paris, and Université Paris Cité, IAME (Infection, Antimicrobial, Modelisation, Evolution), Inserm, Paris, France (B.V.).
³ Emergency Department, Hôpital Henri, Mondor, Assistance Publique - Hôpitaux de Paris, Créteil, France (C.K.).
⁴ Emergency Department, Hôpital Avicenne, Assistance Publique-Hôpitaux de Paris, Bobigny, France (A.D.).
⁵ Emergency Department, Hôpital Européen Georges Pompidou, Assistance Publique-Hôpitaux de Paris, Université Paris Cité, Paris, and Toxicology and Chemical Risks Department, French Armed Forces Biomedical Institute, Bretigny-Sur-Orges, France (F.F.).
⁶ Emergency Department, Hôpital Saint-Antoine, Assistance Publique - Hôpitaux de Paris, Paris, France (C.H.).
⁷ Emergency Department, Hôpital Cochin, Assistance Publique - Hôpitaux de Paris, Université Paris Cité, Paris, France (J.T.).
⁸ Emergency Department, Hôpital Ambroise Paré, Assistance Publique - Hôpitaux de Paris, Université Versailles - Saint Quentin en Yvelines, Boulogne, France (S.B.).
⁹ Emergency Department, Hôpital Louis-Mourier, Assistance Publique - Hôpitaux de Paris, Reference Center for bradykinin angiœdema (CRéAk), Université Paris Cité, Colombes, France (N.J.).
¹⁰ Emergency Department, Hôpital Saint-Louis, Assistance Publique - Hôpitaux de Paris, Paris, France (O.P.).
¹¹ Emergency Department, Hôpital Lariboisière, Assistance Publique - Hôpitaux de Paris, Université Paris Cité, Paris, France (A.C.).
¹² Emergency Department, Hôpital Beaujon, Assistance Publique - Hôpitaux de Paris, Clichy, France (P.V.A.).
¹³ Emergency Department, Hôpital Tenon, Assistance Publique - Hôpitaux de Paris, Paris, France (A.B.).
¹⁴ Sorbonne Université, UMR Inserm 1166, IHU ICAN, and Emergency Department, Hôpital Pitié-Salpêtrière, Assistance Publique - Hôpitaux de Paris, Paris, France (B.R., Y.F.).
¹⁵ Virology Department, Hôpital Pitié-Salpêtrière, Assistance Publique - Hôpitaux de Paris, Paris, France (S.M.).
¹⁶ Emergency Department, Royal London Hospital, London, United Kingdom (B.B.).
¹⁷ Department of Clinical Pharmacology and Clinical Research Platform Paris-East (URCEST-CRC-CRB), Hôpital Saint-Antoine, Assistance Publique-Hôpitaux de Paris, Paris, France (M.C.).
¹⁸ Department of Clinical Pharmacology and Clinical Research Platform Paris-East (URCEST-CRC-CRB), Hôpital Saint-Antoine, Assistance Publique-Hôpitaux de Paris, and Sorbonne Université, Paris, France (T.S.).

Abstract

Background: At the end of 2021, the B.1.1.529 SARS-CoV-2 variant (Omicron) wave superseded the B.1.617.2 variant (Delta) wave.

Objective: To compare baseline characteristics and in-hospital outcomes of patients with SARS-CoV-2 infection with the Delta variant versus the Omicron variant in the emergency department (ED).

Design: Retrospective chart reviews.

Setting: 13 adult EDs in academic hospitals in the Paris area from 29 November 2021 to 10 January 2022.

Patients: Patients with a positive reverse transcriptase polymerase chain reaction (RT-PCR) test result for SARS-CoV-2 and variant identification.

Measurements: Main outcome measures were baseline clinical and biological characteristics at ED presentation, intensive care unit (ICU) admission, mechanical ventilation, and in-hospital mortality.

Results: A total of 3728 patients had a positive RT-PCR test result for SARS-CoV-2 during the study period; 1716 patients who had a variant determination (818 Delta and 898 Omicron) were included. Median age was 58 years, and 49% were women. Patients infected with the Omicron variant were younger (54 vs. 62 years; difference, 8.0 years [95% CI, 4.6 to 11.4 years]), had a lower rate of obesity (8.0% vs. 12.5%; difference, 4.5 percentage points [CI, 1.5 to 7.5 percentage points]), were more vaccinated (65% vs. 39% for 1 dose and 22% vs. 11% for 3 doses), had a lower rate of dyspnea (26% vs. 50%; difference, 23.6 percentage points [CI, 19.0 to 28.2 percentage points]), and had a higher rate of discharge home from the ED (59% vs. 37%; difference, 21.9 percentage points [-26.5 to -17.1 percentage points]). Compared with Delta, Omicron infection was independently associated with a lower risk for ICU admission (adjusted difference, 11.4 percentage points [CI, 8.4 to 14.4 percentage points]), mechanical ventilation (adjusted difference, 3.6 percentage points [CI, 1.7 to 5.6 percentage points]), and in-hospital mortality (adjusted difference, 4.2 percentage points [CI, 2.0 to 6.5 percentage points]).

Limitation: Patients with COVID-19 illness and no SARS-CoV-2 variant determination in the ED were excluded.

Conclusion: Compared with the Delta variant, infection with the Omicron variant in patients in the ED had different clinical and biological patterns and was associated with better in-hospital outcomes, including higher survival.

Primary funding source: None.

MeSH terms

Adult
COVID-19*
Emergency Service, Hospital
Female
Humans
Male
Middle Aged
Paris / epidemiology
Retrospective Studies
SARS-CoV-2* / genetics

Supplementary concepts

SARS-CoV-2 variants