Survival among people hospitalized with COVID-19 in Switzerland: a nationwide population-based analysis

Abstract Background Increasing age, male sex, and pre-existing comorbidities are associated with lower survival from SARS-CoV-2 infection. The interplay between different comorbidities, age, and sex is not fully understood, and it remains unclear if survival decreases linearly with higher ICU occupa...

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Main Authors: Nanina Anderegg, Radoslaw Panczak, Matthias Egger, Nicola Low, Julien Riou
Format: Article
Language:English
Published: BMC 2022-04-01
Series:BMC Medicine
Subjects:
Online Access:https://doi.org/10.1186/s12916-022-02364-7
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author Nanina Anderegg
Radoslaw Panczak
Matthias Egger
Nicola Low
Julien Riou
author_facet Nanina Anderegg
Radoslaw Panczak
Matthias Egger
Nicola Low
Julien Riou
author_sort Nanina Anderegg
collection DOAJ
description Abstract Background Increasing age, male sex, and pre-existing comorbidities are associated with lower survival from SARS-CoV-2 infection. The interplay between different comorbidities, age, and sex is not fully understood, and it remains unclear if survival decreases linearly with higher ICU occupancy or if there is a threshold beyond which survival falls. Method This national population-based study included 22,648 people who tested positive for SARS-CoV-2 infection and were hospitalized in Switzerland between February 24, 2020, and March 01, 2021. Bayesian survival models were used to estimate survival after positive SARS-CoV-2 test among people hospitalized with COVID-19 by epidemic wave, age, sex, comorbidities, and ICU occupancy. Two-way interactions between age, sex, and comorbidities were included to assess the differential risk of death across strata. ICU occupancy was modeled using restricted cubic splines to allow for a non-linear association with survival. Results Of 22,648 people hospitalized with COVID-19, 4785 (21.1%) died. The survival was lower during the first epidemic wave than in the second (predicted survival at 40 days after positive test 76.1 versus 80.5%). During the second epidemic wave, occupancy among all available ICU beds in Switzerland varied between 51.7 and 78.8%. The estimated survival was stable at approximately 81.5% when ICU occupancy was below 70%, but worse when ICU occupancy exceeded this threshold (survival at 80% ICU occupancy: 78.2%; 95% credible interval [CrI] 76.1 to 80.1%). Periods with higher ICU occupancy (>70 vs 70%) were associated with an estimated number of 137 (95% CrI 27 to 242) excess deaths. Comorbid conditions reduced survival more in younger people than in older people. Among comorbid conditions, hypertension and obesity were not associated with poorer survival. Hypertension appeared to decrease survival in combination with cardiovascular disease. Conclusions Survival after hospitalization with COVID-19 has improved over time, consistent with improved management of severe COVID-19. The decreased survival above 70% national ICU occupancy supports the need to introduce measures for prevention and control of SARS-CoV-2 transmission in the population well before ICUs are full.
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spelling doaj.art-10f4a1194e114168b2df68c6619f07232022-12-22T02:28:04ZengBMCBMC Medicine1741-70152022-04-0120111110.1186/s12916-022-02364-7Survival among people hospitalized with COVID-19 in Switzerland: a nationwide population-based analysisNanina Anderegg0Radoslaw Panczak1Matthias Egger2Nicola Low3Julien Riou4Institute of Social and Preventive Medicine, University of BernInstitute of Social and Preventive Medicine, University of BernInstitute of Social and Preventive Medicine, University of BernInstitute of Social and Preventive Medicine, University of BernInstitute of Social and Preventive Medicine, University of BernAbstract Background Increasing age, male sex, and pre-existing comorbidities are associated with lower survival from SARS-CoV-2 infection. The interplay between different comorbidities, age, and sex is not fully understood, and it remains unclear if survival decreases linearly with higher ICU occupancy or if there is a threshold beyond which survival falls. Method This national population-based study included 22,648 people who tested positive for SARS-CoV-2 infection and were hospitalized in Switzerland between February 24, 2020, and March 01, 2021. Bayesian survival models were used to estimate survival after positive SARS-CoV-2 test among people hospitalized with COVID-19 by epidemic wave, age, sex, comorbidities, and ICU occupancy. Two-way interactions between age, sex, and comorbidities were included to assess the differential risk of death across strata. ICU occupancy was modeled using restricted cubic splines to allow for a non-linear association with survival. Results Of 22,648 people hospitalized with COVID-19, 4785 (21.1%) died. The survival was lower during the first epidemic wave than in the second (predicted survival at 40 days after positive test 76.1 versus 80.5%). During the second epidemic wave, occupancy among all available ICU beds in Switzerland varied between 51.7 and 78.8%. The estimated survival was stable at approximately 81.5% when ICU occupancy was below 70%, but worse when ICU occupancy exceeded this threshold (survival at 80% ICU occupancy: 78.2%; 95% credible interval [CrI] 76.1 to 80.1%). Periods with higher ICU occupancy (>70 vs 70%) were associated with an estimated number of 137 (95% CrI 27 to 242) excess deaths. Comorbid conditions reduced survival more in younger people than in older people. Among comorbid conditions, hypertension and obesity were not associated with poorer survival. Hypertension appeared to decrease survival in combination with cardiovascular disease. Conclusions Survival after hospitalization with COVID-19 has improved over time, consistent with improved management of severe COVID-19. The decreased survival above 70% national ICU occupancy supports the need to introduce measures for prevention and control of SARS-CoV-2 transmission in the population well before ICUs are full.https://doi.org/10.1186/s12916-022-02364-7COVID-19SurvivalSARS-CoV-2Intensive care unit
spellingShingle Nanina Anderegg
Radoslaw Panczak
Matthias Egger
Nicola Low
Julien Riou
Survival among people hospitalized with COVID-19 in Switzerland: a nationwide population-based analysis
BMC Medicine
COVID-19
Survival
SARS-CoV-2
Intensive care unit
title Survival among people hospitalized with COVID-19 in Switzerland: a nationwide population-based analysis
title_full Survival among people hospitalized with COVID-19 in Switzerland: a nationwide population-based analysis
title_fullStr Survival among people hospitalized with COVID-19 in Switzerland: a nationwide population-based analysis
title_full_unstemmed Survival among people hospitalized with COVID-19 in Switzerland: a nationwide population-based analysis
title_short Survival among people hospitalized with COVID-19 in Switzerland: a nationwide population-based analysis
title_sort survival among people hospitalized with covid 19 in switzerland a nationwide population based analysis
topic COVID-19
Survival
SARS-CoV-2
Intensive care unit
url https://doi.org/10.1186/s12916-022-02364-7
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