In patients with Covid-19, obesity is the biggest factor associated with the development of endothelial dysfunction – a condition where blood vessels no longer have the ability to contract and relax properly, increasing the risk of events such as heart attack, thrombosis and stroke stroke, according to a release from the São Paulo Research Foundation (FAPESP).
The discovery was made by a team of FAPESP-backed researchers based on data from 109 hospitalized patients with moderate disease conditions. The results were published in Obesity magazine. The information is reported by the FAPESP Agency.
“We performed the general characterization of these patients and tried to identify which factors could modulate or accentuate endothelial damage. The results indicate that the most prevalent item was BMI [índice de massa corporal]. Second, with much less relevance, we find the level of creatinine in the blood, which is a marker linked to renal function,” Alessandro Domingues Heubel, doctoral student in the postgraduate program in physiotherapy at the Federal University of São Carlos (UFSCar) and first author of the article, said in a statement.
Heubel explains that the BMI is one of the chief tools used by health professionals to measure the degree of overweight and obesity. The index is calculated by dividing the weight (in kilograms) by the height (in meters) squared. Individuals with a result equal to or greater than 30 kg / m2 are considered obese.
Patients of both sexes, with an average age of 51, who were at Bauru State Hospital and Santa Casa de São Carlos were included in the research. Obesity was the most common comorbidity (62%) in this population, followed by hypertension (47%) and diabetes (17%).
How did the investigation go?
Blood samples were taken soon after hospital admission, and endothelial function was assessed 72 hours later using a parameter known as flow-mediated dilation (FMD). The non-invasive way has doctors measuring the diameter of the brachial artery, which is located in the arm, by vascular ultrasound examination, before and after a maneuver that obstructs the blood flow to the forearm.
“Immediately after unblocking there is an increase in blood flow in the artery and this constitutes a mechanical stimulus for the endothelial cells [que formam o revestimento interno dos vasos sanguíneos] produce nitric oxide, a vasodilator,” Domingues Heubel said. “The more the artery dilates, the better the endothelial function. And we have seen that obese patients, in a period of active infection with Covid-19, presented very low flow-mediated dilations.”
Along wish foot-and-mouth disease and BMI, grip strength was measured and blood levels of hemoglobin, leukocytes, lymphocytes, platelets, C reactive protein (marker of inflammation) were analyzed, as well as ferritin, D -dimer (marker of thrombosis) and creatinine. The analysis also took into account age, the presence of co-morbidities, physical activity, smoking and drugs used. When the study was taken, no participants were admitted to the intensive care unit (ICU), but 72% were employing oxygen supplementation.
Obesity and creatinine
A univariate regression analysis was performed to find the determinants of endothelial dysfunction in cases. They found that an elevated BMI and creatinine level were directly related to the reduction in foot-and-mouth disease.
According to UFS professor Renata Gonçalves Mendes, Heubel advisor, each additional unit in BMI represented a 0.19% reduction in foot-and-mouth disease.
“When two patients with COVID-19 are compared, one with a normal weight [IMC de 20 kg/m2] and the other with obesity [IMC de 30 kg/m2], the latter tends to have a lower FMD value of 1.9%. Based on prior knowledge, this suggests an increase in cardiovascular risk of around 17%,” the research states.
“In clinical practice, we see that obese people have more cardiovascular events during hospitalization. Our study may help understand one of the mechanisms by which this occurs and why obesity increases the risk of worsening Covid-19,” Mendes said.