Body mass index and severe COVID-19

The COVID-19 pandemic has affected over 60 million people worldwide, of which nearly 1.43 million have died from the severe COVID-19 disease and nearly 40 million have recovered. COVID-19 disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is severe and leads to life-threatening complications in a small percentage of individuals. Several risk factors have been associated with severe COVID-19, including obesity being one.

French researchers led by first author Abdallah Al-Salameh from the Department of Endocrinology, Diabetes Mellitus and Nutrition, Amiens University Hospital, Amiens, France, published the results of their study titled “The association between the class of the body mass index and the 2019 coronavirus disease outcomes, “In the latest issue of International Journal of Obesity.

Background and study objectives

Obesity, high body mass index, and diabetes are known to be risk factors for the severe course of COVID-19. The researchers found from the evidence available in the scientific literature that nearly 40% of hospitalized patients are obese with a high BMI. Morbid obesity, for example, is typically associated with a severe clinical course of the disease they write.

Obesity and COVID-19 pathology

Researchers explain that people with obesity often have impaired respiratory function and this predisposes them to succumb not only to SARS-CoV-2 infection but to other respiratory infections as well.

Additionally, abdominal obesity is associated with low-grade inflammation and this can alter immune responses to infections, including COVID-19 disease. Those with obesity are almost always diabetic and may have heart disease and other metabolic problems, the researchers explain. These comorbidities make them vulnerable to SARS CoV-2 infections, they add.

The main purpose of this study was to quantify the association between body mass index (a measure of obesity) and critical forms of COVID-19. The researchers say this is important for understanding the relationship between obesity and COVID-19 in order to provide care to vulnerable individuals and prevent negative outcomes.

Study design

For this study, the researchers included consecutive adult patients with laboratory-confirmed COVID-19 who needed to be hospitalized. They were all admitted to the university hospital of Amiens (Amiens, France). Patient data was retrospectively collected from the hospital database.

COVID-19 confirmed cases that were confirmed with the reverse transcriptase polymerase chain reaction (RT-PCR) test on nasopharyngeal swab samples. Only patients or their legal guardians who agreed to be part of the study were included in the analysis. For the purposes of this study, normal weight patients were those with a BMI below 25 kg / m².

The important parameters recorded were:

• Demographics including age, gender, BMI, social factors
• Risk factors
• Medical history
• History of taking drugs of particular interest
• Detailed clinical data
• Routine laboratory results
• Patient results

The primary endpoints of the assessment were:

• Admission to the intensive care unit (ICU) e
• Death

The secondary endpoints of the study were:

• Need for mechanical ventilation
• Diagnosis of acute respiratory distress syndrome (ARDS, according to the Berlin criteria) specified in the ICU discharge note
• Diagnosis of acute coronary syndrome (high sensitivity serum cardiac troponin Ic levels above the 99th percentile for normal population, seen on ECG / echocardiogram)
• Acute renal failure (according to Kidney Disease Improving Global Outcomes guidelines)
• Secondary infection
• The total length of hospital stay

Associations between BMI categories and endpoints were made using logistic regression analysis.

Results

A total of 433 patients admitted to hospital with COVID-19 were included in the study. An overview of the results is as follows:

• Among the 329 patients whose BMI was collected, there were:
  • 20 (6.1%) were underweight
  • 95 (28.9 percent) were of normal weight
  • 90 (27.4 percent) were overweight
  • 124 (37.7 percent) were obese
• The median age for the different BMI categories was:
  • Underweight – 84.5 years
  • Normal weight – 81 years
  • Overweight – 71 years
  • Obese – 66 years old
• ICU admission was between 35.1% and 52.6% among overweight and obese patients, respectively
• Deaths were observed in 23% and 36.1% of overweight and obese patients, respectively
• The odds ratio of severe disease associated with the primary endpoint of death or ICU admission according to different BMI categories was as follows:
  • Overweight – Odds ratio 1.58 [0.77–3.24]
  • Obese – Odds ratio 2.58 [1.28–5.31]
• The odds ratio of severe disease associated with ICU admissions according to different BMI categories was as follows:
  • Overweight – Odds ratio 3.16 [1.29–8.06]
  • Obese – Odds ratio 3.05 [1.25–7.82]
• The unadjusted ORs for deaths were the same for all BMI categories

Conclusions and implications

The team writes: “… obesity was significantly associated with a higher likelihood of occurrence of the primary endpoint (death or ICU admission).” Researchers wrote that overweight is more clearly associated with ICU admissions. The team concluded: ‘We found that the frequency of the primary endpoint among COVID-19 patients was twice as high for obese individuals as for individuals with BMI <25 kg / m.². “They asked for future larger studies in other populations to understand the association between BMI and unfavorable outcomes among patients with COVID-19.