key: cord-1037034-ep9moftg
authors: HUANG, Yi; Yao, L.U.; HUANG, Yan-Mei; WANG, Min; LING, Wei; SUI, Yi; ZHAO, Hai-Lu
title: Obesity in patients with COVID-19: a systematic review and meta-analysis
date: 2020-09-28
journal: Metabolism
DOI: 10.1016/j.metabol.2020.154378
sha: 445f41d52d1f02fb48f3b78881a3728007d9d901
doc_id: 1037034
cord_uid: ep9moftg

BACKGROUND: Obesity is common in patients with coronavirus disease 2019 (COVID-19). The effects of obesity on clinical outcomes of COVID-19 warrant systematical investigation. OBJECTIVE: This study explores the effects of obesity with the risk of severe disease among patients with COVID-19. METHODS: Body mass index (BMI) and degree of visceral adipose tissue (VAT) accumulation were used as indicators for obesity status. Publication databases including preprints were searched up to August 10, 2020. Clinical outcomes of severe COVID-19 included hospitalization, a requirement for treatment in an intensive care unit (ICU), invasive mechanical ventilation (IMV), and mortality. Risks for severe COVID-19 outcomes are presented as odds ratios (OR) and 95% confidence interval (95%CI) for cohort studies with BMI-defined obesity, and standardized mean difference (SMD) and 95%CI for controlled studies with VAT-defined excessive adiposity. RESULTS: A total of 45, 650 participants from 30 studies with BMI-defined obesity and 3 controlled studies with VAT-defined adiposity were included for assessing the risk of severe COVID-19. Univariate analyses showed significantly higher ORs of severe COVID-19 with higher BMI: 1.76 (95%: 1.21, 2.56, P = 0.003) for hospitalization, 1.67 (95%CI: 1.26, 2.21, P<0.001) for ICU admission, 2.19 (95%CI: 1.56, 3.07, P<0.001) for IMV requirement, and 1.37 (95%CI: 1.06, 1.75, P = 0.014) for death, giving an overall OR for severe COVID-19 of 1.67 (95%CI: 1.43, 1.96; P<0.001). Multivariate analyses revealed increased ORs of severe COVID-19 associated with higher BMI: 2.36 (95%CI: 1.37, 4.07, P = 0.002) for hospitalization, 2.32 (95%CI: 1.38, 3.90, P = 0.001) for requiring ICU admission, 2.63 (95%CI: 1.32, 5.25, P = 0.006) for IMV support, and 1.49 (95%CI: 1.20, 1.85, P<0.001) for mortality, giving an overall OR for severe COVID-19 of 2.09 (95%CI: 1.67, 2.62; P<0.001). Compared to non-severe COVID-19 patients, severe COVID-19 cases showed significantly higher VAT accumulation with a SMD of 0.49 for hospitalization (95% CI: 0.11, 0.87; P = 0.011), 0.57 (95% CI: 0.33, 0.81; P<0.001) for requiring ICU admission and 0.37 (95% CI: 0.03, 0.71; P = 0.035) for IMV support. The overall SMD for severe COVID-19 was 0.50 (95% CI: 0.33, 0.68; P<0.001). CONCLUSIONS: Obesity increases risk for hospitalization, ICU admission, IMV requirement and death among patients with COVID-19. Further, excessive visceral adiposity appears to be associated with severe COVID-19 outcomes. These findings emphasize the need for effective actions by individuals, the public and governments to increase awareness of the risks resulting from obesity and how these are heightened in the current global pandemic.

The world is witnessing a global pandemic of coronavirus disease 2019 (COVID- 19) , which is considered to be related to infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Most people with COVID-19 appear to develop mild to moderate illness characterized by fever, dry cough and tiredness, and recover without intensive care unit (ICU) admission [1] . In some individuals, however, it may progress to serious conditions such as pneumonia and respiratory failure. As of 10 August 2020, there were 19, 718, 030 confirmed cases and 728, 013 confirmed deaths reported in 216 countries, areas or territories [2] . As the crisis of COVID-19 continues, worldwide efforts have been underway to investigate the disease severity and health complications. Early studies have shed light on risk factors that might drive the disease to be life threatening [3, 4] . Patients who are older and have pre-existing chronic medical conditions, including obesity, cardiovascular diseases, diabetes, cancers and chronic respiratory diseases and kidney diseases were found to be vulnerable to severe COVID-19 [3, 4] .

Of concern，most chronic medical conditions often co-exist with obesity even in patients younger than 60 years of age. As a public health epidemic, obesity affects more than 650 million adults (about 13% of the world's adult population) and 124 million children and adolescents worldwide [5] . Moreover, much clinical research from different affected countries and areas suggests a strong relationship between body mass index (BMI) defined obesity and increased risk of testing positive for SARS-CoV-2 [6] , as well as increased risk of severe disease among patients with COVID-19 [7] [8] [9] [10] . In a prospective cohort study of 233 patients hospitalized with COVID-19 in Italy, patients with obesity had a 3-fold higher risk of death as compared to those with a BMI＜30 kg/m 2 [11] . Among 200 patients with COVID-19 in the Bronx borough of New York City, severe obesity (defined as BMI≥35 kg/m 2 ) was associated with higher in-hospital mortality independent of other pertinent potentially confounding factors [12] . However, a prospective cohort study of non-obesity group using Stata/SE 12.0. We then conducted the effect size combination for all included studies. Pooled OR and 95%CI estimates were calculated using Stata/SE 12.0 to address the relationship between BMI-defined obesity and the risk of defined outcomes among patients with COVID-19. For continuous outcome variables, SMD is a measure of distance between two group means in terms of one or more variables and used as a summary statistic when outcome from each study is measured using several different scales [16] . Since all defined-indicators of quantification of VAT among studies were accepted in our meta-analysis, SMD was used as a summary statistic for included studies to evaluate VAT difference between severe COVID-19 and non-severe COVID-19 groups. The I 2 statistic was used to describe the degree of heterogeneity among the studies. I 2 >50% was considered as high heterogeneity and this allowed us to use the random-effects model, while I 2 ＜50% allowed us to run the fixed-effects model. Potential publication bias was evaluated by visual inspection of funnel plots. Egger's tests were used to assess the symmetry of a funnel plot. The level of statistical significance was defined as P < 0.05.

A total of 9, 916 articles were identified using the search strategies ( Fig. 1) . After removing 2, 753 duplicated records, 7, 163 studies were then screened for title and abstract and 7, 071 were excluded due to having no relevant data or being a non-cohort study. The remaining 92 articles were fully reviewed and 33 studies which met inclusion criteria were included. Among 33 included studies, 30 studies were analyzed to assess the association between BMI and severe COVID-19 while the remaining 3 studies were analyzed to evaluate the association between VAT and severe COVID- 19 there were four studies included to estimate the risk of hospitalization, six studies to estimate the risk of ICU admission, four studies the risk of requiring IMV and seven studies the risk of death. We identified one study from the Bronx borough of New York City reporting a positive association between BMI≥35 kg/m 2 and worse in-hospital outcomes among 200 patients with COVID-19 [12] . In this retrospective cohort study, BMI≥35 kg/m 2 (reference: BMI 25-34 kg/m 2 ) was independently associated with increased risks of intubation (OR: 3.87; 95%CI: 1.47, 10.18; P=0.006) and in-hospital mortality (OR: 3.78; 95%CI:

1.45, 9.83; P=0.006). However, this valuable study provided no available data on defined obesity group (BMI≥30 kg/m 2 ) and therefore was not included in our meta-analysis. Among the other three included studies reporting VAT as variable, there were two studies included to estimate the risk of hospitalization, three studies the risk of ICU admission, two studies the risk of needing IMV and no studies to estimate the risk of death. We indentified only one article reporting an association between VAT area and death related to COVID-19 [15] . However, this research was finally excluded from our study as there was no available data of VAT area for the survivor group.

The included studies involved 9 countries over the world including USA, Italy, China, Spain, The state of Kuwait, Mexico, France, Switzerland and Greece. A total of 45, 650 participants were finally included into analysis. Nearly two third of the studies (18/33) were from USA, the current epicenter of the coronavirus pandemic. A retrospective study design was used in the majority of included studies (87.9%, 29/33). We identified five studies, which didn't report their study type as retrospective studies according to their study methods [7, 9, [17] [18] [19] . Only one of the included studies was designed as a retrospective and prospective study [20] . Patients mainly participated in these studies between February to May. The participants in 20 studies were all adults, over 18 years of age, while 11 studies did not report the age range of their participants in detail. Only one study included exclusively children with a median age of 13.1 (0. 4-19.3) from Italy defined a BMI of over 29 kg/m 2 as obesity [22] . It should be noted that one study emphasized that the World Health Organization defined obesity as abnormal or excessive fat accumulation that presents a risk to health [14] . No obesity definition was given in six studies [17, 20, [23] [24] [25] [26] . The percentage of people with obesity among valid participants of all but one of the included studies ranged from 10.9% to 61.3%, with only one study below 10% ( Table 1) . Among three studies that aimed to evaluate the association between VAT and severe COVID-19, a CT measurement was performed to quantify VAT. One study defined VAT as the greatest distance between the inner muscular wall and the anterior liver surface and therefore assessed VAT amount by thickness [25] , whereas two other studies [14, 26] assessed VAT amount by area (Table B. Supplementary appendix B) . In the two studies, VAT content was evaluated at different abdominal levels of CT scan: the first slice where lung bases were no longer visible at the thoracoabdominal level in one study [14] and the axial slice at the superior end plate of L3 vertebral body in the other study [26] .

Using the NOS method, studies included in the present analysis had an average score of 8, with 22 studies achieved 8 or 9 scores and were then considered as cohort study of high quality. Eleven studies achieved scores of 5 to 7 and thus were considered as moderate quality ( Table 2 ).

Pooled effects of univariate analysis of included studies indicated that BMI-defined obesity increased risk of severe disease among patients with COVID-19, as shown in Fig. 2 Furthermore, since Paleodimos and colleagues reported the importance of severe obesity as a critical component to COVID-19 severity in the cohort of the Bronx borough of New York City [12] , we included their study in our meta-analysis and performed a summary estimation ( 

Pooled summary effects of multivariate analysis of included studies also suggested that BMI-defined obesity increased risk of severe disease and death among patients with COVID-19, as shown in Fig. 3 .

After adjusting for covariate factors, COVID-19 patients with obesity were also at a high risk of needing 

Compared to the non-severe COVID-19 group, VAT accumulation levels were significantly higher in COVID-19 patients with a severe condition. For the hospitalized group versus those not hospitalized, the SMD was 0.49 (95% CI: 0.11, 0.87; P = 0.011), For the ICU admission group versus those not admitted to ICU, the SMD was 0.57 ( 95% CI: 0.33, 0.81; P＜0.001) and for the IMV group versus those not needing J o u r n a l P r e -p r o o f Journal Pre-proof IMV, the SMD was 0.37 (95% CI: 0.03, 0.71; P=0.035) (Fig. 4) . The overall estimated effect was statistically significant (SMD = 0.50, 95% CI: 0.33, 0.68; P＜0.001) (Fig. 4) , indicating that the more VAT accumulation a COVID-19 patient had, the more severe the clinical condition they might develop. 

Our study confirms that obesity may increase the risks of hospitalization, ICU admission, the necessity for IMV, and death among patients with COVID-19. An early systematic review addressed that obesity was a predictor for a worse prognosis of COVID-19 with a total of three cohort studies included [27] . Previous meta-analysis studies indicated that COVID-19 patients with higher BMI were at a greater risk of medical complications [28] , ICU admission [29, 30] , IMV intervention [29, 30] , death [31, 32] and poor composite outcomes [31, 33, 34] . Findings in our study are consistent with those reports, suggesting a positive relationship between higher BMI and increased risk of disease severity among patients with COVID-19.

In terms of method, both univariate and multivariate analyses of the association between high BMI and clinical outcomes were performed in our meta-analysis to provide a contrast among study results, which differs from previous similar meta-analyses. Moreover, previous meta-analyses focused mainly on the association between BMI-defined obesity and COVID-19 severity. However BMI does not reflect the distribution of body fat and therefore these research analyses fail to demonstrate the impact of excess body fat in different parts of the body on COVID-19 severity. To the best of our knowledge, this is the first meta-analysis to identify a positive relationship between high VAT accumulation and severe COVID-19.

Obesity prevalence among hospitalized COVID-19 patients can reach up to 61.3%, according to an American study from our included articles [35] . In addition to the impact of obesity on the risk of hospitalization, this may also due to high prevalence of obesity in American population. [37] . Of particular note is that BMI threshold differs between Asian and Caucasian populations, and health risks among these two groups can be different at any given BMI. Despite the lower prevalence of BMI-defined obesity, awareness of a potentially similar obesity-related risk of COVID-19 should be not be delayed by Asian countries.

Since older age has been well recognized as an important risk factor of suffering a severe condition of COVID-19, we should be cautious about applying the findings of our meta-analysis to children. Most infected children appear to experience more favorable outcomes than adults [38] . The study we included that examined children had a relatively small subject number and did not find an association between obesity and increased likelihood of pediatric intensive care unit admission [21] . However, a significant inverse correlation between age and BMI was reported among 265 patients admitted to ICU, meaning that obesity could shift severe COVID-19 disease to younger ages [39] . On the other hand, two studies we included found that the effect of BMI ≥30 kg/m 2 on COVID-19 severity or death among adults was age-dependent [10, 40] . Compared to younger patients, older COVID-19 patients with BMI≥30kg/m 2 appeared to develop a less severe condition [10, 40] . Nevertheless, it's worth noting that the gradient of risk of severe COVID-19 in relation to BMI might be more gradual among older patients when compared to younger individuals [41] . This may be attributed to the fact that BMI is a less accurate predictor of excess fat in older adults with lower muscle mass, together with a shift from subcutaneous fat to VAT and increased relative fat mass among them [14] . A more precise measurement of excess fat may help predict more reliable health risks in this group with obesity. The positive relationship between VAT and severe COVID-19 in our meta-analysis may provide an important insight.

The underlying mechanism by which obesity increases the risk of severe covid-19 remains unknown.

Previous research has shown that obesity was related to a worse outcome as a result of infection and disease progression for certain kinds of infectious virus diseases, such as influenza in the 1918 "Spanish" influenza pandemic [42, 43] and may be mildly hypoxaemic [47] . A greater oxygen cost of breathing was needed for patients with J o u r n a l P r e -p r o o f Journal Pre-proof obesity when compared to those without obesity, even at rest [47] . In a recently published meta-analysis, dyspnea rather than fever was shown to be significantly associated with the risk of mortality among COVID-19 patients [48] . One study we included found that BMI≥30kg/m 2 were associated with the risk of hypoxemia upon hospital admission among patients with COVID-19 (OR: 1.7, 95%CI: 1.3, 2.1; P<0.0005) [35] . A BMI≥35 kg/m 2 was even a significant predictor for increasing oxygenation requirement in a cohort of COVID-19 patients in the Bronx borough of New York City [12] . In the children-included study [21] , shortness of breath was found to be the only clinical symptom that was associated with pediatric intensive care unit admission. Patients diagnosed with obesity hypoventilation syndrome developed typical hypoxaemia and hypercapnia, and may suffer a higher risk of severe condition when infected with SARS-CoV-2 [49] . Therefore, obesity-related hypoxaemia might be an important contributor to COVID-19 severity among those with obesity. This may explain why COVID-19 patients with obesity were at a greater risk of needing IMV, as shown by results in our study.

Obesity also increases the risk of many common non-communicable diseases such as diabetes mellitus, cardiovascular disorders, cancers and non-alcoholic fatty liver disease, and often co-exists with them in a single individual. These co-existing co-morbidities are considered to increase the likelihood of severe illness from COVID-19 for people with obesity [50] [51] [52] . Excessive adipose tissue including ectopic fat may serve as reservoirs for angiotensin-converting enzyme 2 (ACE2) and microbes such as coronavirus, influenza A virus and mycobacterium tuberculosis [53] . Beyond disease severity, obesity increased the duration of influenza A virus shedding to hasten virus spreading mainly for person-to-person transmission [54] . Moreover, college volunteers with symptomatic seasonal influenza who had higher BMI have been found to generate more infectious aerosols [55] . These findings may also extend to COVID-19.

Above all, combined adipose tissue-mediated immune and metabolic dysfunctions might play a key role in the pathophysiological pathways that lead obesity to influence COVID-19 prognosis [46, 56, 57] .

Low-grade systemic inflammation and increasing insulin resistance commonly exists in people with obesity [58, 59] . and this immune and metabolic phenomena is strongly associated with presence of excess VAT [56] . Visceral obesity-related impaired immune response can also lead to systemic metabolic dysfunction [43, 56] and increase risks of metabolic disorders and cardiovascular diseases, as well as their complications [61] [62] [63] . Furthermore, while BMI on its own does not reflects any particular distribution of body fat, VAT is a marker of increased ectopic fat that might contribute to increased atherosclerosis and cardiometabolic risk [64] . Excessive visceral adiposity may provide additional important information about COVID-19 risk, which is not captured in BMI. Evidence of value from two recent studies, which were not included in our analysis due to our study design and eligibility criteria, suggests that visceral adiposity increases the likelihood of severe COVID-19 [15, 65] . Central obesity is defined as a state of excessive VAT accumulation [66] . Patients with central obesity evidenced by waist circumference or waist-to-hip ratio were also found to be more likely to develop severe COVID-19 (P ＜ 0.001) in a large population-based cohort [67] . Our primary analysis also demonstrates a more VAT accumulation among patients with severe COVID-19. For the sake of comparison, we also extracted data on subcutaneous adipose tissue (SAT) from the included 3 controlled studies with VAT-defined adiposity, and performed a separate meta-analysis to evaluate SAT accumulation with the risk of severe COVID-19 (Table D The present study assesses the risk of severe COVID-19 with obesity, using not only BMI but also VAT measures, and this is the main strength of our study. There are also several limitations to be acknowledged.

First, some participants we included might overlap, because some of our included studies are from the same affected area or city and both single-center and multi-center studies were included in our meta-analysis.

Second, despite our study seeking to investigate the role of VAT accumulation in the risk of severe COVID-19, diagnostic cut-off points by VAT amount for obesity of the three included studies could not be set in our meta-analysis since no accepted standards of diagnostic criteria by VAT quantification for obesity were available. Third, while fat mass can be classified as VAT, SAT, ectopic fat (intra-muscular fat, myocardial steatosis, fatty liver, atheroma, et al), and blood lipids (dyslipidemia) we have only evaluated the impact of VAT and SAT on COVID-19 prognosis. A comprehensive assessment of the relationship J o u r n a l P r e -p r o o f between excess fat mass and the risk of severe COVID-19 will require a thorough literature search and extensive future investigation. Fourth, in our study, the effects of combining all included studies could lead to a bias due to the adjusted confounders for BMI or obesity state varying between the included studies, particularly in the absence of adjusting for some unrecognized factors. Last, since the vast majority of included studies were designed as retrospective, a causal relationship between obesity and COVID-19 severity and death should not be identified.

Our study suggests that obesity increases risk for hospitalization, ICU admission, need for IMV and death among patients with COVID-19. Further, excessive visceral adiposity appears to be associated with severe COVID-19 outcomes. The clinical outcomes of communicable disease such as COVID-19 might also depend on obesity status. These findings emphasize the need for effective actions by individuals, the public and governments to increase awareness of the risks resulting from obesity and how these are heightened in the current global pandemic. J o u r n a l P r e -p r o o f ICU, intensive care unit; IMV, invasive mechanical ventilation; VAT, visceral adipose tissue. § Statistical description of age was presented as Mean ± Standard Deviation. ¶ We identified these five studies, which didn't report their study type as retrospective studies according to their study methods. † Proportion of male among total valid participants.

J o u r n a l P r e -p r o o f Table 2 . Quality assessment of included studies using the Newcastle-Ottawa Scale (NOS)

Study ID Representativeness of the exposed cohort Selection of the non exposed cohort Ascertainment of exposure Demonstration that outcome of interest was not presentatstart of study 

Risk factors for SARS-CoV-2 among patients in the Oxford Royal College of General Practitioners Research and Surveillance Centre primary care network: a cross-sectional study

Factors associated with hospitalization and critical illness among 4,103 patients with COVID-19 disease in New York City

High Prevalence of Obesity in Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) Requiring Invasive Mechanical Ventilation

Obesity and COVID-19 Severity in a Designated Hospital in Shenzhen

Obesity in patients younger than 60 years is a risk factor for Covid-19 hospital admission

30-day mortality in patients hospitalized with COVID-19 during the first wave of the Italian epidemic: A prospective cohort study

When continuous outcomes are measured using different scales: guide for meta-analysis and interpretation

A cohort of patients with COVID-19 in a major teaching hospital in Europe

Interim Analysis of Risk Factors for Severe Outcomes among a Cohort of Hospitalized Adults Identified through the U.S. Coronavirus Disease 2019 (COVID-19)-Associated Hospitalization Surveillance Network (COVID-NET)

Pre-Existing Traits Associated with Covid-19 Illness Severity

Early experience with COVD-19 patients at tertiary care teaching hospital in southwestern United states

Clinical Characteristics and Outcomes of Hospitalized and Critically Ill Children and Adolescents with

COVID-19) at a Tertiary Care Medical Center in New York City

Lung disease severity, Coronary Artery Calcium, Coronary inflammation and Mortality in Coronavirus Disease

Characteristics and outcomes of a cohort of SARS-CoV-2 patients in the Province of Reggio Emilia

Early estimation of the risk factors for hospitalisation and mortality by COVID-19 in Mexico

Computed Tomography critical condition in COVID-19 patients: A systematic review and meta-analysis

Body Mass Index and Outcome in Patients with COVID-19: A Dose-Response Meta-Analysis

Obesity aggravates COVID-19: a systematic review and meta-analysis

Association of BMI and Obesity with Composite poor outcome in COVID-19 adult patients: A Systematic Review and Meta-Analysis

Obesity is Associated with Increased Risk for Mortality Among Hospitalized Patients with COVID-19

World Health Organization. Prevalence of obesity among adults, BMI ≥ 30

Coronavirus Infection in Pediatric Emergency Departments Research G. Children with Covid-19 in Pediatric Emergency Departments in Italy

Obesity could shift severe COVID-19 disease to younger ages

Severe Obesity as an Independent Risk Factor for COVID-19 Mortality in Hospitalized Patients Younger than 50

BMI and future risk for COVID-19 infection and death across sex, age and ethnicity: Preliminary findings from UK biobank

Back to the Future: Lessons Learned From the 1918 Influenza Pandemic

Impact of obesity on respiratory function

Dyspnea rather than fever is a risk factor for predicting mortality in patients with COVID-19

Letter to the Editor: Obesity hypoventilation syndrome and severe COVID-19

Commentary: Obesity: The "Achilles heel" for COVID-19?

Comorbidities and the risk of severe or fatal outcomes associated with coronavirus disease 2019: A systematic review and meta-analysis

Letter to the Editor: Obesity as a risk factor for greater severity of COVID-19 in patients with metabolic associated fatty liver disease

Risk of COVID-19 for patients with obesity

Obesity Increases the Duration of Influenza A Virus Shedding in Adults

Infectious virus in exhaled breath of symptomatic seasonal influenza cases from a college community

Obesity and COVID-19: immune and metabolic derangement as a possible link to adverse clinical outcomes

Obesity Is a Risk Factor for Severe COVID-19 Infection: Multiple Potential Mechanisms

COVID-19 and the role of chronic inflammation in

Association between visceral and subcutaneous adipose depots and incident cardiovascular disease risk factors

Visceral and ectopic fat, atherosclerosis, and cardiometabolic disease: a position statement

The role of visceral adiposity in the severity of COVID-19: Highlights from a unicenter cross-sectional pilot study in Germany

A dose-response relation between aerobic exercise and visceral fat reduction: systematic review of clinical trials

Obesity & genetic predisposition with COVID-19

30-day mortality in patients hospitalized with COVID-19 during the first wave of the Italian epidemic: A prospective cohort study

A cohort of patients with COVID-19 in a major teaching hospital in Europe

Association of Obesity with Disease Severity among Patients with COVID-19

Clinical Characteristics and Outcomes of Hospitalized and Critically Ill Children and Adolescents with

COVID-19) at a Tertiary Care Medical Center in New York City

Characteristics and outcomes of a cohort of SARS-CoV-2 patients in the Province of Reggio Emilia

Characterization and clinical course of 1000 Patients with COVID-19 in New York: retrospective case series

COVID-19: Impact of Obesity and Diabetes in Disease Severity

Factors associated with hospital admission and critical illness among 5279 people with coronavirus disease 2019 in New York City: prospective cohort study

Derivation of a score to predict admission to intensive care unit in patients with COVID-19: The ABC-GOALS score

Factors Associated With Intubation and Prolonged Intubation in Hospitalized Patients With COVID-19

Determinants of Severity in Cancer Patients with COVID-19 Illness

Early estimation of the risk factors for hospitalisation and mortality by COVID-19 in Mexico

High Prevalence of Obesity in Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) Requiring Invasive Mechanical Ventilation

Early experience with COVD-19 patients at tertiary care teaching hospital in southwestern United states

Severe Obesity as an Independent Risk Factor for COVID-19 Mortality in Hospitalized Patients Younger than 50

Obesity and COVID-19 Severity in a Designated Hospital in Shenzhen

risk factors and clinical course of SARS-CoV-2 infected patients in a Swiss university hospital: an observational retrospective study

Obesity in patients younger than 60 years is a risk factor for Covid-19 hospital admission

Factors associated with hospitalization and critical illness among 4,103 patients with COVID-19 disease in New York City

Interim Analysis of Risk Factors for Severe Outcomes among a Cohort of Hospitalized Adults Identified through the U.S. Coronavirus Disease 2019 (COVID-19)-Associated Hospitalization Surveillance Network (COVID-NET)

Lung disease severity, Coronary Artery Calcium, Coronary inflammation and Mortality in Coronavirus Disease

Pre-Existing Traits Associated with Covid-19 Illness Severity

Sociodemographic predictors of outcomes in COVID-19: examining the impact of ethnic disparities in Northern Nevada

Demographic and clinical features of critically ill patients with COVID-19 in Greece: The burden of diabetes and obesity

How important is obesity as a risk factor for respiratory failure, intensive care admission and death in hospitalised COVID-19 patients? Results from a single Italian centre

Increased Risk for Mortality Among Hospitalized Patients with COVID-19

The impact of obesity on COVID-19 complications: a retrospective cohort study

Visceral adipose tissue in patients with COVID-19: risk stratification for severity

Computed Tomography Highlights Increased Visceral Adiposity Associated With Critical Illness in COVID-19

Visceral fat shows the strongest association with the need of intensive Care in Patients with COVID-19

We are grateful to Dr. Phil Griffiths for his work revising the written English in our text.

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