key: cord-0746808-bm2dmhi6
authors: Heubel, Alessandro Domingues; Viana, Ariane Aparecida; Linares, Stephanie Nogueira; do Amaral, Vanessa Teixeira; Schafauser, Nathany Souza; de Oliveira, Gustavo Yudi Orikassa; Ramírez, Paula Camila; Martinelli, Bruno; da Silva Alexandre, Tiago; Borghi‐Silva, Audrey; Ciolac, Emmanuel Gomes; Mendes, Renata Gonçalves
title: Determinants of endothelial dysfunction in noncritically ill hospitalized COVID‐19 patients: A cross‐sectional study
date: 2021-11-23
journal: Obesity (Silver Spring)
DOI: 10.1002/oby.23311
sha: 6daa7ab50c9789248339e841ca138d6661492ec9
doc_id: 746808
cord_uid: bm2dmhi6

OBJECTIVE: The aim of this study was to identify determinants of endothelial dysfunction in patients hospitalized with acute COVID‐19. METHODS: A total of 109 hospitalized COVID‐19 patients in noncritical status were cross‐sectionally studied. Clinical data (age, sex, comorbidities, and medications) and BMI were assessed. Laboratory tests included serum hemoglobin, leukocytes, lymphocytes, platelets, C‐reactive protein, ferritin, D‐dimer, and creatinine. Physical status was evaluated using a handgrip dynamometer. Endothelial function was assessed noninvasively using the flow‐mediated dilation (FMD) method. RESULTS: The sample average age was 51 years, 51% of patients were male, and the most frequent comorbidity was obesity (62%). Univariate analysis showed association of lower FMD with higher BMI, hypertension, use of oral antihypertensive, higher blood levels of creatinine, and larger baseline artery diameter. After adjusting for confounders, the multivariate analysis showed BMI (95% CI: −0.26 to −0.11; p < 0.001) as the major factor associated with FMD. Other factors associated with FMD were baseline artery diameter (95% CI: −1.77 to −0.29; p = 0.007) and blood levels of creatinine (95% CI: −1.99 to −0.16; p = 0.022). CONCLUSIONS: Increased BMI was the major factor associated with endothelial dysfunction in noncritically hospitalized COVID‐19 patients. This may explain one of the pathways in which obesity may increase the risk for severe COVID‐19.

COVID-19 is an infectious disease caused by SARS-CoV-2. Most cases of COVID-19 are mild, but 20% of the patients require hospitalization because of severe manifestations such as dyspnea and respiratory failure (1) . Although COVID-19 is widely known for its respiratory symptoms as a result of viral pneumonia, the disease can also cause several extrapulmonary manifestations (2) . In part, these manifestations result from systemic damage caused by the viral infection of multiple organs, including the brain, intestine, kidneys, heart, and blood vessels (3) .

A strong theoretical rationale for multisystemic involvement is that COVID-19 is, in the end, an endothelial disease (4) . Postmortem histological findings have already revealed that patients with severe COVID-19 have endothelial injury in multiple vascular beds of the lungs, kidney, and heart (5) . As consequence, a dysfunctional endothelium has a negative impact on the control of hemostasis, fibrinolysis, vasomotion, inflammation, and vascular permeability (4) . These conditions are also determinants for many complications of severe COVID-19, such as cardiovascular events (6) , kidney injury (7), acute respiratory distress syndrome (8) , and coagulation abnormalities (9) .

In fact, there is an expert consensus stating that COVID-19 is associated with endothelial dysfunction, and this relationship is recognized as crucial for the pathogenesis and disease severity (4, (10) (11) (12) .

However, during acute COVID-19, some clinical conditions may also interact to modulate endothelial damage. For example, aging, physical inactivity, and comorbidities (e.g., hypertension, diabetes, obesity), which are conditions associated with severe COVID-19 (12) (13) , are also independent risk factors for endothelial dysfunction (14) .

Other potential COVID-19-associated conditions include systemic hyperinflammation and procoagulant state, considered hallmarks of severe disease and which have the endothelium acting as an important regulator (15) . Therefore, even though risk factors for endothelial dysfunction are known in other non-COVID-19 conditions, little is known about associated factors during acute COVID-19. This knowledge is important for a better understanding of the effects of SARS-CoV-2 on endothelial biology and, more specifically, for identifying the susceptibility characteristics for endothelial dysfunction during COVID-19, with possible implications for targeted therapies. In this study, we aimed to identify the factors associated with endothelial dysfunction in patients hospitalized with acute COVID-19.

This is an observational, cross-sectional, double-center study including patients hospitalized with suspected COVID- 19 

A bedside clinical anamnesis and physical examination were performed to obtain demographic characteristics, detailed history of disease with time since first symptoms, smoking habit, comorbidities, body weight and height, and use of oxygen therapy. BMI was calculated as weight in kilograms divided by height in meters squared, and patients were classified into underweight (BMI < 18.5), normal weight (BMI = 18.5-24.9), overweight (BMI = 25.0-29.9), and obesity (BMI ≥ 30.0) (16) . Current smokers were defined as patients who were smoking at the time of study or who had stopped smoking during the last month prior to the study. Vital signs such as body temperature, blood pressure (BP), heart rate, respiratory rate, and Study Importance

► Endothelial dysfunction is associated with COVID-19 and plays a central role in the pathogenesis, complications, and severity of disease.

► Even during viral infection, endothelial damage can be modulated by several clinical conditions such as comorbidities, physical status, inflammation, and coagulation.

► Increased BMI was identified as the major factor associated with endothelial dysfunction in noncritically ill hos- pulse oxygen saturation (SpO 2 ) were assessed at rest. Medications in use were obtained from the electronic patient record.

Complete blood count was used to assess serum hemoglobin, leukocytes, lymphocytes, and platelets. Inflammation and coagulation profile were evaluated by serum levels of C-reactive protein (CRP), ferritin, and D-dimer. COVID-19-associated hyperinflammatory syndrome (COV-HI) was characterized as a CRP concentration greater than 150 mg/L or a ferritin concentration greater than 1,500 mg/dL (17) . Blood creatinine were analyzed as a marker of kidney function.

All laboratory data were obtained at hospital admission.

The endothelium-dependent function was assessed using the noninvasive and standardized method of flow-mediated dilation (FMD) (18) . Before measurement, patients rested in supine position for at least 10 minutes, and a BP cuff was positioned on their forearm.

An ultrasound device (SonoSite M-Turbo, FUJIFILM) was used to evaluate blood flow velocity and brachial artery diameter, which were recorded continuously for 1 minute pre-cuff inflation and 3 minutes post-cuff release during hyperemia. All assessments were performed by an experienced operator with more than 100 scans/y, which is suggested to maintain competency with the FMD method (19) . In order to ensure accurate FMD measures, we respected the recommendations for technique execution and data acquisition (19) . Doppler blood flow and artery diameter analyses in B-mode video images were performed using an edge-detection and wall 

After FMD measurement, physical status was assessed by grip strength, which was evaluated using a Jamar hydraulic dynamometer (Performance Health). In order to perform the measurement, the patient was positioned seated, with the elbow flexed at 90 degrees and the wrist in neutral. At least three measures were performed for each hand, and the greater of the two averaged values was recorded for the final grip strength value (20) .

Data with normal distribution are reported as mean (SD), whereas data with nonnormal distribution are presented as median (25-75 interquartile range). Categorical variables are shown as absolute frequency (percentage). First, univariate analysis was used to investigate relationships between FMD and underlying clinical conditions. Control variables with a p < 0.20 in the univariate analyses were incorporated into the multivariate model using the stepwise forward method, and those with a p < 0.05 in the final model were considered to be significantly associated with the outcome (FMD) (21) . In order to avoid multicollinearity, a variance inflation factor < 5 was considered to include variables in the model (22) . The final model was adjusted for age, sex, comorbidities, physical status, hyperinflammatory syndrome, and D-dimer blood level. All statistical tests were performed in Stata 15 software (StataCorp).

A total of 132 patients were evaluated, of which, 11 were excluded after COVID-19 diagnosis was not confirmed, and 12 were excluded because of missing data. Therefore, 109 COVID-19 patients were included in the final analysis (Table 1 ). Average age of studied population was 51 years, and 51% of the patients were male. The most frequent comorbidity was obesity (62%), followed by hypertension (47%) and diabetes (17%). No patient was underweight (BMI < 18.5).

The average time since first symptoms was 12 days, and the six most frequent COVID-19-related symptoms were cough (88%), dyspnea (87%), fever (84%), fatigue (73%), myalgia (70%), and headache (62%).

Vital signs showed suboptimal control of heart rate (80 [15] Most patients were using supplemental oxygen (72%) to maintain SpO 2 93% [4%]. All patients were using prophylactic anticoagulant, and most were using antibiotic (91%), corticosteroid (87%), and oral antihypertensive (51%) medications.

Univariate regression analysis showed an association between lower FMD and higher BMI, hypertension diagnosis, use of oral antihypertensive, higher blood levels of creatinine, and larger baseline artery diameter (Table 2 ). After adjusting for potential confounders, Table 3 ).

The present study investigated the determinants of endothelial dysfunction in noncritically ill patients hospitalized due to COVID-19.

As the main finding, we found a cross-sectional association between endothelial dysfunction assessed by FMD and higher BMI in patients hospitalized during acute COVID-19. Analysis of possible underlying factors revealed that larger baseline artery diameter and elevated blood levels of creatinine were also associated with lower FMD.

Previous studies have reported that, in patients with COVID-19, obesity has been associated with poor outcomes such as increased disease severity, hospitalization, intensive care unit admission, need for invasive mechanical ventilation, and mortality (23) . In our study, obesity was the most prevalent comorbidity (62%), followed by hypertension (47%) and diabetes (17%). Other observational studies with hospitalized COVID-19 patients have also found a high prevalence of obesity, with rates of 61%, 48%, and 42%, respectively (24) (25) (26) . These findings tend to confirm that patients with obesity are more prone to severe COVID-19, with a consequent need for hospital admission.

There are some hypotheses on the mechanisms underpinning the association between obesity and severe COVID-19. This higher risk has been suggested to be due to chronic inflammation, impairment of respiratory function and pulmonary perfusion, critical care Male sex, n (%) 55 (51) BMI (kg/m 2 ) 32.6 ± 6.8

Normal weight, n (%) 14 (12) Overweight, n (%) 28 (26) Obesity, n (%) 67 (62) Current smoker, n (%) 10 (9) Hypertension, n (%) 51 (47) Diabetes, n (%) 19 (17) Asthma, n (%) 8 (7) Heart failure, n (%) 7 (6) Days of symptoms ( (27) . In our study, we showed that people with obesity and/or a higher BMI had a worse endothelial function during acute COVID-19. In practice, this finding corroborates previous speculation that has suggested that endothelial dysfunction may explain, at least in part, one of the mechanisms by which obesity increases the risk for severe COVID-19 (28) . Translating these findings into clinical practice, it is important to highlight prior knowledge that a 1% decrease in FMD is associated with a 9% increase in the risk of cardiovascular events (32) . As our study revealed a β coefficient of −0.19 in the association between BMI and FMD, this means that for each additional unit (kilograms per meters squared) in BMI, a 0.19% decrease in FMD is expected.

In a practical context, when two COVID-19 patients, one with normal weight (BMI of 20) and the other with obesity (BMI of 30), are compared, the latter tends to have a 1.9% lower FMD. This could also be speculated as an elevated cardiovascular risk of more than 17%. Interestingly, our results may support other larger population studies in which an increased risk for vascular events was observed among hospitalized COVID-19 patients with obesity. For example, in a retrospective study on 7,606 patients hospitalized with COVID-19, the presence of obesity was found to be associated not only with an increased risk of in-hospital death, but also with a high risk of venous thromboembolism (33) . Similar evidence was found in a retrospective cohort of 609 patients hospitalized for COVID-19, in which class I and III subgroups of patients with obesity had significantly higher riskadjusted odds of venous thromboembolism compared with patients without obesity (34) .

On the other hand, even in the absence of SARS-CoV-2 infection, obesity is a condition often associated with endothelial dysfunction.

Possible underlying mechanisms are diverse and include insulin resistance, increased free fatty acids, oxidative stress, and low grade of chronic inflammatory state (35) . However, during the active phase of COVID-19, there is a hypothesis suggesting that patients with obesity have an amplified inflammatory state in a phenomenon already known as "cytokine storm" (36) . In our study, although the patients had high median levels of CRP and ferritin, we did not find a relationship between the hyperinflammatory syndrome (COV-HI) and the degree of endothelial dysfunction. However, some concerns must be raised. First, laboratory tests were obtained early on in hospital admission and were not temporally accurate with FMD assessments.

As FMD assessment was performed within 72 hours after admission, the patient's inflammatory status may have changed, especially after administration of corticosteroid treatment (87% were receiving).

Furthermore, even though CRP is an inflammatory marker widely used in clinical practice, there is no perfect association or linear temporal response with other pro-inflammatory mediators such as interleukin 6 and procalcitonin (37) , which also have a negative influence on endothelial function.

Another finding of our study was the association between en- in order to obtain a more detailed profile of the endothelial function.

As a fourth limitation, we consider the lack of further investigation of the inflammatory profile. Although not routinely applied in clinical practice, the quantification of pro-inflammatory cytokines, including interleukin-6, could contribute to a better understanding of the role of the COVID-19-associated cytokine storm in endothelial dysfunction.

The fifth and last limitation was that we did not assess nitroglycerinmediated vascular dilation, which can be used to quantify maximal vascular dilation independently of endothelium. Therefore, we were unable to determine whether vasodilation was impaired only because of the inability of endothelial cells to release nitric oxide but also by a loss in arterial smooth-muscle cell integrity.

Increased BMI was identified as a major factor associated with endothelial dysfunction in noncritically ill hospitalized COVID-19

patients. This finding may explain, at least partially, one of the pathways in which obesity may increase the risk for the development of severe COVID-19. Future studies should assess whether COVID-19 patients with obesity might benefit from a more intense therapeutic strategy to attenuate endothelial dysfunction.O

We would like to thank the Bauru State Hospital (HEB/FAMESP) and

the Holy House of São Carlos for supporting the development of this research.

The authors declared no conflict of interest. 

Audrey Borghi-Silva https://orcid.org/0000-0002-3891-6941

Renata Gonçalves Mendes https://orcid.org/0000-0003-4683-2657

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