The COVID-19 pandemic emphasizes the need to manage patient obesity

Obesity has been associated with 236 medical diseases, including 13 types of cancers. COVID-19 is the latest addition to this growing list of medical illnesses.

CDC listed obesity as one of the risk factors linked to severe illness from COVID-19, emphasizing the need for patients to take weight issues more seriously than ever. Obesity triples the rate of hospitalization from COVID-19, and obesity-related comorbidities worsen the outcome. Recent studies have illustrated a direct relationship between BMI and severity of the symptoms, including mortality from COVID-19 infection.

The prevalence of obesity among children and adults continues to rise. According to the CDC, 12 states in the US had an adult obesity prevalence rate of 35% or above in 2019, a dramatic but expected increase from 2018 (9 states) and 2017 (6 states). With the recent change in the lifestyle imposed on us due to this pandemic, this number will only continue to grow if we do not take adequate measures to curtail it.

How does this disease state caused by adipose tissue dysfunction lead to a spiraling cascade of metabolic, inflammatory, and mechanical derangement when exposed to a severe infection like COVID-19?

Let us explore some of the reasons:

Obesity and immune function: Clinical and epidemiological data have shown that obesity impairs the immune response. The incidence and severity of certain types of infectious diseases are higher among obese persons than lean individuals due to altered antibody response. The imbalance between energy intake and expenditure typically seen in obesity may also influence cell-mediated and humoral immune response. Research has shown a strong negative correlation between the T-cell population and its function with body weight.

Obesity and lung function: Obesity decreases total lung capacity, functional residual capacity, increases airway resistance, and makes mechanical ventilation more difficult. Acute respiratory distress syndrome due to COVID-19 requiring mechanical ventilation has been more prevalent in patients with a BMI greater than 30 and most significant in patients with a BMI greater than 35. ARDShas been the major complication and cause of death in COVID‐19. Obesity plays a crucial role in susceptibility to ARDS, respiratory failure, and outcome with mechanical ventilation due to baseline lung physiology changes with impaired ventilation and gas exchange. Obstructive sleep apnea that is often seen in obese patients increases the risk of hypoventilation‐associated pneumonia, pulmonary hypertension, and sudden cardiac death.

Obesity and comorbidities: Obesity is closely associated with chronic illnesses like DM, HTN, etc. DM/hyperglycemia impairs the immune response, thereby making the patient more susceptible to pneumonia and nosocomial infections. Hypertension is an independent risk factor associated with severe COVID-19 infection, ARDS, and mortality as per a recent meta-analysis study.

1. Obesity and metabolic dysfunction: Obesity is a metabolic disease characterized by alterations in metabolic functions, like insulin resistance, hyperglycemia, increased leptin, decreased adiponectin, and chronic low‐grade inflammation. The accumulation of pro‐inflammatory immune cells like macrophages in the adipose tissues along with increased serum inflammatory cytokines have been proposed as critical mediators of COVID‐19 severity in individuals with obesity. SARS‐CoV‐2 enters the cells through ACE‐2 receptors found abundantly in adipose tissues, thereby predisposing a person with excessive weight to COVID-19 infection.
2. Obesity and physical limitation: Large body mass makes it difficult to provide supportive treatments such as intubation, skincare, and positioning. Abdominal, visceral adiposity and fatty liver often present in obese patients can lead to atelectasis, further exacerbated by supine positioning and sedatives.
3. Obesity and response to treatment: Obesity poses therapeutic challenges in the treatment of COVID-19. IL-6 antagonist tocilizumab used in severe COVID‐19 cases where cytokine release syndrome is a significant cause of mortality. However, in individuals with obesity with a chronic inflammatory status with elevated IL‐6, treatment with tocilizumab may not be beneficial. Similarly, obese individuals have shown a blunted immune response to vaccines like influenza, hepatitis, etc., making preventative measures challenging as well.

Obesity is a chronic, complicated, multifactorial disease that has been causing a substantial medical and economic burden. As per the World Health Organization, in 2016, more than 1.9 billion adults aged 18 years and older were overweight. Of these, over 650 million adults were obese. Obesity has long been a global health issue, a slowly ravaging pandemic.

The COVID-19 pandemic has put obesity in the spotlight, illustrating the need to focus on screening and treating it more aggressively than before. Until we have a vaccine for COVID-19, we are left with only preventive measures — wearing masks to curtail the spread of the contagion and diet to trim the waistline.

Aparna Chandrasekaran, M.D., is medical director of the Jersey Medical Weight Loss Center, a member of the Center for Medical Weight Loss and a committee member and mentor in the Obesity Medicine Association.

References

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2. T lymphopaenia in relation to body mass index and TNF‐α in human obesity: adequate weight reduction can be corrective. Clinical endocrinology, 54(3), 347-354.

3. High prevalence of obesity in severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2) requiring invasive mechanical ventilation. Obesity. Obesity Reviews September 2020. Effect of obesity and body mass index on coronavirus disease 2019 severity: A systematic review and meta‐analysis

4.Individuals with obesity and COVID‐19: A global perspective on epidemiology and biological relationships. Obesity reviews. August 2020.

5.Effect of obesity and body mass index on coronavirus disease 2019 severity: A systematic review and meta‐analysis. Obesity Reviews September 2020.

6. Hypertension is associated with increased mortality and severity of disease in COVID-19 pneumonia: A systematic review, meta-analysis, and meta-regression. Pubmed.gov

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8. WHO. https://www.who.int/health-topics/obesity