Increasingly a link found between obesity and COVID-19 outcome risk

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Following the devastating outbreak of COVID-19 in China in December and January, details began to emerge of the risk factors predisposing sufferers to the more serious manifestations and to the risk of death.

The Daily Telegraph reports that an early review, based on 191 patients in Wuhan, who had died or been discharged from hospital, together with findings from other studies, indicated that risks were greatest among older patients, especially males. Other factors included a history of cardiovascular disease, diabetes, respiratory disorders, immune suppression and cancer – in that order.

Since then, the report says, further studies have indicated a high frequency of obese patients that have been admitted to intensive care units with the virus and requiring invasive mechanical ventilation, and that the severity of the disease seems to increase with their body mass index (weight in kg divided by height in metres squared).

Obesity then emerged as a predictor of poor outcome. At this time, many experts assumed the link with obesity could be accounted for by the well-known association between obesity and type 2 diabetes. However, the report says, a number of peer reviewed articles have since been published in respected journals from countries, especially in Europe and the US, where obesity is highly prevalent. Findings from one study in France in particular, indicates that severe obesity (BMI of 35 or more) may be a risk factor for severe illness and invasive mechanical ventilation, independent of age and whether or not patients may be suffering from diabetes or hypertension. Another study, from the US, found a significant difference in admission and ICU in patients, younger than 60 years of age, but with increased BMI.

The report says this raises questions as to what exactly it is about obesity that may predispose the body to severe viral impact.

Our understanding of obesity has been changing in recent years along with the increased research effort that has accompanied its recognition as a burgeoning non-communicable public health disease around the world. Levels vary in relation to a range of associated disorders that may reduce the quality of life and life expectancy. It is a chronic disease, whose origins are influenced by the interplay of our genes, the environment, and human behaviour.

The report says in recent years we have become far more aware of the notion of “obesogenic” environments in which our surroundings and living conditions, including the availability of fast food outlets and processed food, for example, can drive obesity.

The report says the experience of COVID-19 has shone a new light on obesity; one that may cause us to rethink our current ideas about obesity and about the nature of fat as other than an inert tissue but rather as an organ in its own right with complex interactions with the immune system and with inflammatory processes.

The Lancet abstract (Southern University of Science and Technology/ Guangzhou Medical University)
Background: Patients with obesity are at increased risk of exacerbations from viral respiratory infections. However, the association of obesity with severity of corona virus disease 2019 (COVID-19) is unclear. We hereby examined this association using data from the only referral hospital in Shenzhen, China.
Methods: 383 COVID-19 patients admitted from 11 January to 16 February 2020 in the Third People’s Hospital of Shenzhen, China were included. Underweight was defined by body mass index (BMI) lower than 18·5 kg/m2, normal weight by 18·5-23·9 kg/m2 , overweight by 24·0- 27·9 kg/m2 and obesity as ≥28 kg/m2.
Findings: Of them, 53·1% were normal weight, 4·2% were underweight, 32·0% were overweight, and 10·7% were obese. Patients with obesity, versus without, were tended to have cough (P=0·03) and fever (P=0·06). After adjusting for potential confounders, compared to normal weight, overweight showed 86% higher, and obesity group showed 2·42-fold higher odds of developing severe pneumonia. Despite a non-significant sex interaction was found (P=0·09), the association appeared to be more pronounced in men than in women. The odds ratios (95% confidence intervals) for severe pneumonia in overweight and obesity was 1·96 (0·78-4·98) and 5·70 (1·83-17·76) in men, and 1·51 (0·57-4·01) and 0·71 (0·07-7·3) in women, respectively.

Interpretation: This is the first study showing that obesity, especially in men, significantly increases the risk of developing severe pneumonia in COVID-19 patients. As the 2019n-Cov may continue to spread worldwide, clinicians should maintain a high level of attention in obese patients. Obese patients should be carefully managed with prompt and aggressive treatment.

Cai Qingxian; Fengjuan Chen

medRxiv abstract (NYU Grossman School of Medicine/NYU Langone Health)
Background: Little is known about factors associated with hospitalization and critical illness in Covid-19 positive patients.
Methods: We conducted a cross-sectional analysis of all patients with laboratory-confirmed Covid-19 treated at an academic health system in New York City between March 1, 2020 and April 2, 2020, with follow up through April 7, 2020. Primary outcomes were hospitalization and critical illness (intensive care, mechanical ventilation, hospice and/or death). We conducted multivariable logistic regression to identify risk factors for adverse outcomes, and maximum information gain decision tree classifications to identify key splitters.

Results: Among 4,103 Covid-19 patients, 1,999 (48.7%) were hospitalized, of whom 981/1,999 (49.1%) have been discharged, and 292/1,999 (14.6%) have died or been discharged to hospice. Of 445 patients requiring mechanical ventilation, 162/445 (36.4%) have died. Strongest hospitalization risks were age ≥75 years (OR 66.8, 95% CI, 44.7-102.6), age 65-74 (OR 10.9, 95% CI, 8.35-14.34), BMI>40 (OR 6.2, 95% CI, 4.2-9.3), and heart failure (OR 4.3 95% CI, 1.9- 11.2). Strongest critical illness risks were admission oxygen saturation 2500 (OR 6.9, 95% CI, 3.2-15.2), ferritin >2500 (OR 6.9, 95% CI, 3.2-15.2), and C-reactive protein (CRP) >200 (OR 5.78, 95% CI, 2.6-13.8). In the decision tree for admission, the most important features were age >65 and obesity; for critical illness, the most important was SpO20.5, troponin 64 and CRP>200.
Conclusions: Age and comorbidities are powerful predictors of hospitalization; however, admission oxygen impairment and markers of inflammation are most strongly associated with critical illness.

Christopher M Petrilli, Simon A Jones, Jie Yang, Harish Rajagopalan, Luke O’Donnell, Yelena Chernyak, Katie A Tobin, Robert J Cerfolio, Fritz Francois, Leora I Horwitz

Full report in The Daily Telegraph

The Lancet Infectious Diseases abstract

Clinical Infectious Diseases abstract

medRxiv abstract

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