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Body Mass Index and clinical outcome of severe COVID-19 patients with acute hypoxic respiratory failure: unravelling the “obesity paradox” phenomenon

Body Mass Index and clinical outcome of severe COVID-19 patients with acute hypoxic respiratory failure: unravelling the “obesity paradox” phenomenon
Body Mass Index and clinical outcome of severe COVID-19 patients with acute hypoxic respiratory failure: unravelling the “obesity paradox” phenomenon
Background and aims
Although obesity have been generally shown to be an independent risk factor for poor outcomes in COVID-19 infection, some studies demonstrate a paradoxical protective effect (“obesity paradox”). This study examines the influence of obesity categories on clinical outcomes of severe COVID-19 patients admitted to an intensive care unit with acute hypoxic respiratory failure requiring either non-invasive or invasive mechanical ventilation.

Methods
This is a single centre, retrospective study of consecutive COVID-19 patients admitted to the intensive care unit between 03/2020 to 03/2021. Patients were grouped according to the NICE Body Mass Index (BMI) category. Admission variables including age, sex, comorbidities, and ICU severity indices (APACHE-II, SOFA and PaO2/FiO2) were collected. Data were compared between BMI groups for outcomes such as need for invasive mechanical ventilation (IMV), renal replacement therapy (RRT) and 28-day and overall hospital mortality.

Results
340 patients were identified and of those 333 patients had their BMI documented. Just over half of patients (53%) had obesity. Those with extreme obesity (obesity groups II and III) were younger with fewer comorbidities, but were more hypoxaemic at presentation, than the healthy BMI group. Although non-significant, obesity groups II and III paradoxically showed a lower in-hospital mortality than the healthy weight group. However, adjusted (age, sex, APACHE-II and CCI) competing risk regression analysis showed three-times higher mortality in obese category I (sub-distribution hazard ratio = 3.32 (95% CI 1.30–8.46), p = 0.01) and a trend to higher mortality across all obesity groups compared to the healthy weight group.

Conclusions
In this cohort, those with obesity were at higher risk of mortality after adjustment for confounders. We did not identify an “obesity paradox” in this cohort. The obesity paradox may be explained by confounding factors such as younger age, fewer comorbidities, and less severe organ failures. The impact of obesity on indicators of morbidity including likelihood of requirement for organ support measures was not conclusively demonstrated and requires further scrutiny.

Acute hypoxic respiratory failure, Body mass index, COVID-19, Intensive care, Invasive mechanical ventilation, Obesity
2405-4577
377 - 384
Jennings, Michael
fbf12ac7-5c03-4523-b89b-7f4d007e46c3
Burova, Maria
ce82b538-760f-446a-8c01-803c818ddb84
Hamilton, Laura G.
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Hunter, Elsie
15769f4c-9a09-4e1c-8ae3-e50ad631b74e
Mordena, Clare
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Beecham, Ryan
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Pandya, Darshni
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Moyses, Helen
91efd231-965d-4cb1-b50b-d0448a74f989
Saeed, Kordo
87cb67e5-71e8-4759-bf23-2ea00ebd8b39
Afolabi, Paul
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Calder, Philip
1797e54f-378e-4dcb-80a4-3e30018f07a6
Dushianthan, Ahilanandan
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Wilkinson, Thomas
8c55ebbb-e547-445c-95a1-c8bed02dd652
Freeman, Anna
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Celinski, Michael
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Faust, Saul
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Thomas, Gareth J
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Kipps, Christopher
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REACT COVID-19 investigators
Jennings, Michael
fbf12ac7-5c03-4523-b89b-7f4d007e46c3
Burova, Maria
ce82b538-760f-446a-8c01-803c818ddb84
Hamilton, Laura G.
3bd9f419-f3b5-4aa6-8c63-6a4be80c2ed1
Hunter, Elsie
15769f4c-9a09-4e1c-8ae3-e50ad631b74e
Mordena, Clare
e65f2d8f-508f-4d83-9fd7-b2bc3307c95d
Beecham, Ryan
4238fd35-1fd7-4534-bdd7-7a0e4c34f535
Pandya, Darshni
547f248e-077b-44bc-8a7b-65a11d7da712
Moyses, Helen
91efd231-965d-4cb1-b50b-d0448a74f989
Saeed, Kordo
87cb67e5-71e8-4759-bf23-2ea00ebd8b39
Afolabi, Paul
757e7f01-664c-493e-bc51-c6a2c933dc22
Calder, Philip
1797e54f-378e-4dcb-80a4-3e30018f07a6
Dushianthan, Ahilanandan
f4d6308b-91ae-4073-a18d-288db1f70893
Wilkinson, Thomas
8c55ebbb-e547-445c-95a1-c8bed02dd652
Freeman, Anna
b5f45a0d-f9e4-4a91-9af0-40efb6730787
Celinski, Michael
f5ddadb6-e935-476c-ab46-0423a031a83b
Faust, Saul
f97df780-9f9b-418e-b349-7adf63e150c1
Thomas, Gareth J
2ff54aa9-a766-416b-91ee-cf1c5be74106
Kipps, Christopher
e43be016-2dc2-45e6-9a02-ab2a0e0208d5

Jennings, Michael, Burova, Maria, Hamilton, Laura G., Hunter, Elsie, Mordena, Clare, Beecham, Ryan, Pandya, Darshni, Moyses, Helen, Saeed, Kordo, Afolabi, Paul, Calder, Philip and Dushianthan, Ahilanandan , REACT COVID-19 investigators (2022) Body Mass Index and clinical outcome of severe COVID-19 patients with acute hypoxic respiratory failure: unravelling the “obesity paradox” phenomenon. Clinical Nutrition ESPEN, 51, 377 - 384. (doi:10.1016/j.clnesp.2022.07.016).

Record type: Article

Abstract

Background and aims
Although obesity have been generally shown to be an independent risk factor for poor outcomes in COVID-19 infection, some studies demonstrate a paradoxical protective effect (“obesity paradox”). This study examines the influence of obesity categories on clinical outcomes of severe COVID-19 patients admitted to an intensive care unit with acute hypoxic respiratory failure requiring either non-invasive or invasive mechanical ventilation.

Methods
This is a single centre, retrospective study of consecutive COVID-19 patients admitted to the intensive care unit between 03/2020 to 03/2021. Patients were grouped according to the NICE Body Mass Index (BMI) category. Admission variables including age, sex, comorbidities, and ICU severity indices (APACHE-II, SOFA and PaO2/FiO2) were collected. Data were compared between BMI groups for outcomes such as need for invasive mechanical ventilation (IMV), renal replacement therapy (RRT) and 28-day and overall hospital mortality.

Results
340 patients were identified and of those 333 patients had their BMI documented. Just over half of patients (53%) had obesity. Those with extreme obesity (obesity groups II and III) were younger with fewer comorbidities, but were more hypoxaemic at presentation, than the healthy BMI group. Although non-significant, obesity groups II and III paradoxically showed a lower in-hospital mortality than the healthy weight group. However, adjusted (age, sex, APACHE-II and CCI) competing risk regression analysis showed three-times higher mortality in obese category I (sub-distribution hazard ratio = 3.32 (95% CI 1.30–8.46), p = 0.01) and a trend to higher mortality across all obesity groups compared to the healthy weight group.

Conclusions
In this cohort, those with obesity were at higher risk of mortality after adjustment for confounders. We did not identify an “obesity paradox” in this cohort. The obesity paradox may be explained by confounding factors such as younger age, fewer comorbidities, and less severe organ failures. The impact of obesity on indicators of morbidity including likelihood of requirement for organ support measures was not conclusively demonstrated and requires further scrutiny.

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Accepted/In Press date: 29 July 2022
e-pub ahead of print date: 6 August 2022
Published date: October 2022
Additional Information: Funding Information: We thank all the members of the REACT study group and the GICU consultants' group. The REACT study group consist of Tom Wilkinson, Anna Freeman, Hannah Burke, Michael Celinski, Saul N Faust, Gareth J Thomas, and Christopher Kipps. Name and location of the institution where the study was conducted: General Intensive Care Unit, University Hospital Southampton NHS Foundation Trust, UK. Publisher Copyright: © 2022 European Society for Clinical Nutrition and Metabolism
Keywords: Acute hypoxic respiratory failure, Body mass index, COVID-19, Intensive care, Invasive mechanical ventilation, Obesity

Identifiers

Local EPrints ID: 470442
URI: http://eprints.soton.ac.uk/id/eprint/470442
ISSN: 2405-4577
PURE UUID: 3e06450d-21a9-416e-8d5b-388ebbf4c164
ORCID for Kordo Saeed: ORCID iD orcid.org/0000-0003-0123-0302
ORCID for Paul Afolabi: ORCID iD orcid.org/0000-0002-0553-1578
ORCID for Philip Calder: ORCID iD orcid.org/0000-0002-6038-710X
ORCID for Anna Freeman: ORCID iD orcid.org/0000-0003-3495-2520
ORCID for Saul Faust: ORCID iD orcid.org/0000-0003-3410-7642

Catalogue record

Date deposited: 11 Oct 2022 16:33
Last modified: 17 Mar 2024 07:26

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Contributors

Author: Michael Jennings
Author: Maria Burova
Author: Laura G. Hamilton
Author: Elsie Hunter
Author: Clare Mordena
Author: Ryan Beecham
Author: Darshni Pandya
Author: Helen Moyses
Author: Kordo Saeed ORCID iD
Author: Paul Afolabi ORCID iD
Author: Philip Calder ORCID iD
Author: Ahilanandan Dushianthan
Author: Anna Freeman ORCID iD
Author: Michael Celinski
Author: Saul Faust ORCID iD
Author: Gareth J Thomas
Author: Christopher Kipps
Corporate Author: REACT COVID-19 investigators

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