Evolution of outcomes for patients hospitalised during the first 9 months of the SARS-CoV-2 pandemic in France: A retrospective national surveillance data analysis

Noémie Lefrancq; Juliette Paireau; Nathanaël Hozé; Noémie Courtejoie; Yazdan Yazdanpanah; Lila Bouadma; Pierre-Yves Boëlle; Fanny Chereau; Henrik Salje; Simon Cauchemez

doi:10.1016/j.lanepe.2021.100087

Evolution of outcomes for patients hospitalised during the first 9 months of the SARS-CoV-2 pandemic in France: A retrospective national surveillance data analysis

Lancet Reg Health Eur. 2021 Jun:5:100087. doi: 10.1016/j.lanepe.2021.100087. Epub 2021 Mar 21.

Authors

Noémie Lefrancq^{1

2}, Juliette Paireau^{1

3}, Nathanaël Hozé¹, Noémie Courtejoie⁴, Yazdan Yazdanpanah^{5

6}, Lila Bouadma^{5

7}, Pierre-Yves Boëlle⁸, Fanny Chereau³, Henrik Salje^{1

2}, Simon Cauchemez¹

Affiliations

¹ Mathematical Modelling of Infectious Diseases Unit, Institut Pasteur, UMR2000, CNRS, Paris, France.
² Department of Genetics, University of Cambridge, Cambridge, UK.
³ Santé Publique France, French National Public Health Agency, Saint-Maurice, France.
⁴ DREES, Ministère des Solidarités et de la Santé, Paris, France.
⁵ Université of Paris, INSERM UMR 1137 IAME, Paris, France.
⁶ Department of Infectious Diseases, Assistance Publique-Hôpitaux de Paris, Bichat-Claude-Bernard University Hospital, Paris, France.
⁷ Medical and Infectious Diseases Intensive Care Unit, Assistance Publique-Hôpitaux de Paris, Bichat-Claude-Bernard University Hospital, Paris, France.
⁸ Institut Pierre Louis d'Epidémiologie et de Santé Publique, Sorbonne Université, INSERM, Paris, France.

Abstract

Background: As SARS-CoV-2 continues to spread, a thorough characterisation of healthcare needs and patient outcomes, and how they have changed over time, is essential to inform planning.

Methods: We developed a probabilistic framework to analyse detailed patient trajectories from 198,846 hospitalisations in France during the first nine months of the pandemic. Our model accounts for the varying age- and sex- distribution of patients, and explore changes in outcome probabilities as well as length of stay.

Findings: We found that there were marked changes in the age and sex of hospitalisations over the study period. In particular, the proportion of hospitalised individuals that were >80y varied between 27% and 48% over the course of the epidemic, and was lowest during the inter-peak period. The probability of hospitalised patients entering ICU dropped from 0·25 (0·24-0·26) to 0·13 (0·12-0·14) over the four first months as case numbers fell, before rising to 0·19 (0·19-0·20) during the second wave. The probability of death followed a similar trajectory, falling from 0·25 (0·24-0·26) to 0·10 (0·09-0·11) after the first wave before increasing again during the second wave to 0·19 (0·18-0·19). Overall, we find both the probability of death and the probability of entering ICU were significantly correlated with COVID-19 ICU occupancy.

Interpretation: There are large scale trends in patients outcomes by age, sex and over time. These need to be considered in ongoing healthcare planning efforts.

Funding: INCEPTION.