From the Journals

Obesity link to severe COVID-19, especially in patients aged under 60


Obesity in under 60s at least doubles risk of admission in U.S.

The studies out of New York, one of which was stratified by age, paint a similar picture.

Dr. Lighter and colleagues found that, of the 3,615 individuals who tested positive for COVID-19 in their series, 775 (21%) had a BMI of 30-34 and 595 (16%) had a BMI of at least 35. Obesity wasn’t a predictor of admission to hospital or the ICU in those over the age of 60 years, but in those younger than 60 years, it was.

Those under age 60 with a BMI of 30-34 were twice as likely to be admitted to hospital (hazard ratio, 2.0; P < .0001) and critical care (HR, 1.8; P = .006), compared with those under age 60 with a BMI less than 30. Likewise, those under age 60 with a BMI of at least 35 were 2.2 (P < .0001) and 3.6 (P < .0001) times more likely to be admitted to acute and critical care.

“Unfortunately, obesity in people [less than] 60 years is a newly identified epidemiologic risk factor which may contribute to increased morbidity rates [with COVID-19] experienced in the U.S.,” they concluded.

And in the other U.S. study, Christopher M. Petrilli, MD, of New York University, and colleagues looked at 4,103 patients with COVID-19 treated between March 1 and April 2, 2020, and followed to April 7.

Just under half of patients (48.7%) were hospitalized, of whom 22.3% required mechanical ventilation and 14.6% died or were discharged to hospice. The research was published on medRxiv, showing that, apart from age, the strongest predictors of hospitalization were BMI greater than 40 (OR, 6.2) and heart failure (OR, 4.3).

“It is notable that the chronic condition with the strongest association with critical illness was obesity, with a substantially higher odds ratio than any cardiovascular or pulmonary disease,” they noted.

Inflammation is a possible culprit

Dr. Pattou believes that the culprit behind the increased risk of disease severity seen with obesity in COVID-19 is inflammation, mediated by fibrin deposits in the circulation, which his colleagues have seen on autopsy, and which “block oxygen passage through the blood.”

This may help explain why mechanical ventilation can be less successful in these patients. “The answer is to get rid of this inflammation,” Dr. Pattou observed.

Dr. Petrilli and colleagues also observed that obesity “is well-recognized to be a proinflammatory condition.”

And their findings showed “the importance of inflammatory markers in distinguishing future critical from noncritical illness,” they said, noting that, among these markers, early elevations in C-reactive protein and D-dimer “had the strongest association with mechanical ventilation or mortality.”

Livio Luzi, MD, of IRCCS MultiMedica, Milan, Italy, has previously written on the relationship between influenza and obesity, and discussed in an interview the potential lessons for the COVID-19 pandemic.

“Obesity is characterized by an impairment of immune response and by a low-grade chronic inflammation. Furthermore, obese subjects have an altered dynamic of pulmonary ventilation, with reduced diaphragmatic excursion,” Dr. Luzi said. These factors, alongside others, “may help to explain” the current results, and stress the importance of close monitoring of those with obesity and COVID-19.

No relevant financial relationships were declared.

This article first appeared on


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