Editor’s note: Find the latest COVID-19 news and guidance in Medscape’s Coronavirus Resource Center.
In a large California healthcare plan, among patients with COVID-19, men aged 60 years and younger had a much higher risk of dying within 3 weeks of diagnosis if they had severe obesity as opposed to being of normal weight, independently of other risk factors.
The research shows that “obesity plays a profound role in risk for death from COVID-19, particularly in male patients and younger populations,” Sara Y. Tartof, PhD, MPH, Kaiser Permanente Southern California, Pasadena, California, and coauthors report.
The data “highlight the leading role of severe obesity over correlated risk factors, providing a target for early intervention,” they conclude in an article published online August 12 in Annals of Internal Medicine.
This work adds to nearly 300 articles that have reported that severe obesity is associated with an increased risk for morbidity and mortality from COVID-19.
In an accompanying editorial, David A. Kass, MD, says: “Consistency of this new study and prior research should put to rest the contention that obesity is common in severe COVID-19 because it is common in the population.”
Rather, these findings show that “obesity is an important independent risk factor for serious COVID-19 disease,” he points out.
On the basis of this evidence, “arguably the hardest question to answer is: What is to be done?” wonders Kass, from Johns Hopkins University, Baltimore, Maryland.
Although data consistently show that a body mass index (BMI) >35 kg/m2 is predictive of major health risks, “weight reduction at that level of obesity is difficult and certainly is not achieved rapidly,” Kass stresses.
“Therefore…social distancing; altering behaviors to reduce viral exposure and transmission, such as wearing masks; and instituting policies and health care approaches that recognize the potential effects of obesity should be implemented,” he emphasizes. “These actions should help and are certainly doable.”
Similarly, Tartof and colleagues say their “findings also reveal the distressing collision of 2 pandemics: COVID-19 and obesity.
“As COVID-19 continues to spread unabated, we must focus our immediate efforts on containing the crisis at hand,” they urge.
However, the findings also “underscore the need for future collective efforts to combat the equally devastating, and potentially synergistic, force of the obesity epidemic.”
COVID-19 Pandemic Collides With Obesity Epidemic
Previous studies of obesity and COVID-19 were small, did not adjust for multiple confounders, or did not include nonhospitalized patients, Tartof and coauthors write.
Their study included 6916 members of the Kaiser Permanente Southern California healthcare plan who were diagnosed with COVID-19 from February 13 to May 2, 2020.
The researchers calculated the risk for death at 21 days after a COVID-19 diagnosis; findings were corrected for age, sex, race/ethnicity, smoking, myocardial infarction, congestive heart failure, peripheral vascular disease, cerebrovascular disease, chronic pulmonary disease, renal disease, metastatic tumor or malignancy, other immune disease, hyperlipidemia, hypertension, asthma, organ transplant, and diabetes status.
On the basis of BMI, the patients were classified as being underweight, of normal weight, overweight, or as having class 1, 2, or 3 obesity. BMI of 18.5 to 24 kg/m2 is defined as normal weight.
Class 3 obesity, also called severe obesity, included moderately severe obesity (BMI, 40 – 44 kg/m2) and extremely severe obesity (≥45 kg/m2).
A little more than half of the patients were women (55%), and more than 50% were Hispanic (54%).
A total of 206 patients (3%) died within 21 days of being diagnosed with COVID-19; of these, 67% had been hospitalized, and 43% had been intubated.
Overall, the COVID-19 patients with moderately severe or extremely severe obesity had a 2.7-fold and 4.2-fold increased risk for death, respectively, within 3 weeks compared to patients of normal weight.
Patients in the other BMI categories did not have a significantly higher risk of dying during follow-up.
However, each decade of increasing age after age 40 was associated with a stepwise increased risk for death within 3 weeks of the COVID-19 diagnosis.
Risk Stratified by Age and Sex
Further analysis showed that, “most strikingly,” among patients aged 60 and younger, those with moderately severe obesity and extremely severe obesity had significant 17-fold and 12-fold higher risks of dying during follow-up, respectively, compared with patients of normal weight, the researchers report.
In patients older than 60, moderately severe obesity did not confer a significant increased risk for imminent death from COVID-19; extremely severe obesity conferred a smaller, threefold increased risk for this.
“Our finding that severe obesity, particularly among younger patients, eclipses the mortality risk posed by other obesity-related conditions, such as history of myocardial infarction (MI), diabetes, hypertension, or hyperlipidemia, suggests a significant pathophysiologic link between excess adiposity and severe COVID-19 illness,” according to the researchers.
This independent increased risk for death with severe obesity was seen in men but not in women.
Men with moderately severe and extremely severe obesity had significant 4.8-fold and 10-fold higher risks of dying within 3 weeks, respectively, compared to men of normal weight.
“That the risks are higher in younger patients is probably not because obesity is particularly damaging in this age group; it is more likely that other serious comorbidities that evolve later in life take over as dominant risk factors,” Kass suggests in his editorial.
“That males are particularly affected may reflect their greater visceral adiposity over females, given that this fat is notably proinflammatory and contributes to metabolic and vascular disease,” he added.
“As a cardiologist who studies heart failure,” Kass writes, “I am struck by how many of the mechanisms that are mentioned in reviews of obesity risk and heart disease are also mentioned in reviews of obesity and COVID-19.”
The study was funded by Roche-Genentech. Kass has disclosed no relevant financial relationships. Disclosures of the authors are listed in the article.
Ann Intern Med. Published online August 12, 2020. Full text, Editorial
For more diabetes and endocrinology news, follow us on Twitter and Facebook.