In a global meta-analysis of more than 7,000 patients who were hospitalized with COVID-19, individuals with overweight or obesity were more likely to need respiratory support but were not more likely to die in the hospital, compared to individuals of normal weight.
Compared to patients without diabetes, those with diabetes had higher odds of needing invasive respiratory support (with intubation) but not for needing noninvasive respiratory support or of dying in the hospital.
“Surprisingly,” among patients with diabetes, being overweight or having obesity did not further increase the odds of any of these outcomes, the researchers wrote. The finding needs to be confirmed in larger studies, they said, because the sample sizes in these subanalyses were small and the confidence intervals were large.
The study by Danielle K. Longmore, PhD, of Murdoch Children’s Research Institute (MCRI), Melbourne, and colleagues from the International BMI-COVID consortium, was published online April 15 in Diabetes Care.
This new research “adds to the known data on the associations between obesity and severe COVID-19 disease and extends these findings” to patients who are overweight and/or have diabetes, Dr. Longmore, a pediatric endocrinologist with a clinical and research interest in childhood and youth obesity, said in an interview.
Immunologist Siroon Bekkering, PhD, of Radboud University Medical Center, Nijmegen, the Netherlands, explained that never before have so much data of different types regarding obesity been combined in one large study. Dr. Bekkering is a coauthor of the article and was a principal investigator.
“Several national and international observations already showed the important role of overweight and obesity in a more severe COVID-19 course. This study adds to those observations by combining data from several countries with the possibility to look at the risk factors separately,” she said in a statement from her institution.
“Regardless of other risk factors (such as heart disease or diabetes), we now see that too high a BMI [body mass index] can actually lead to a more severe course in [coronavirus] infection,” she said.
Study implications: Data show that overweight, obesity add to risk
These latest findings highlight the urgent need to develop public health policies to address socioeconomic and psychological drivers of obesity, Dr. Longmore said.
“Although taking steps to address obesity in the short term is unlikely to have an immediate impact in the COVID-19 pandemic, it will likely reduce the disease burden in future viral pandemics and reduce risks of complications like heart disease and stroke,” she observed in a statement issued by MCRI.
Coauthor Kirsty R. Short, PhD, a research fellow at the University of Queensland, Brisbane, Australia, noted that “obesity is associated with numerous poor health outcomes, including increased risk of cardiometabolic and respiratory disease and more severe viral disease including influenza, dengue, and SARS-CoV-1.
“Given the large scale of this study,” she said, “we have conclusively shown that being overweight or obese are independent risk factors for worse outcomes in adults hospitalized with COVID-19.”
“At the moment, the World Health Organization has not had enough high-quality data to include being overweight or obese as a risk factor for severe COVID-19 disease,” added another author, David P. Burgner, PhD, a pediatric infectious diseases clinician scientist from MCRI.
“Our study should help inform decisions about which higher-risk groups should be vaccinated as a priority,” he observed.
Does being overweight up risk of worse COVID-19 outcomes?
About 13% of the world’s population are overweight, and 40% have obesity. There are wide between-country variations in these data, and about 90% of patients with type 2 diabetes are overweight or obese, the researchers noted.
The Organisation for Economic Co-operation and Development reported that the prevalence of obesity in 2016-2017 was 5.7% to 8.9% in Asia, 9.8% to 16.8% in Europe, 26.5% in South Africa, and 40.0% in the United States, they added.
Obesity is common and has emerged as an important risk factor for severe COVID-19. However, most previous studies of COVID-19 and elevated BMI were conducted in single centers and did not focus on patients with overweight.
To investigate, the researchers identified 7,244 patients (two-thirds were overweight or obese) who were hospitalized with COVID-19 in 69 hospitals (18 sites) in 11 countries from Jan. 17, 2020, to June 2, 2020.
Most patients were hospitalized with COVID-19 in the Netherlands (2,260), followed by New York City (1,682), Switzerland (920), St. Louis (805), Norway, Italy, China, South Africa, Indonesia, Denmark, Los Angeles, Austria, and Singapore.
Just over half (60%) of the individuals were male, and 52% were older than 65.
Overall, 34.8% were overweight, and 30.8% had obesity, but the average weight varied considerably between countries and sites.
Increased need for respiratory support, same mortality risk
Compared with patients with normal weight, patients who were overweight had a 44% increased risk of needing supplemental oxygen/noninvasive ventilation, and those with obesity had a 75% increased risk of this, after adjustment for age (< 65, ≥ 65), sex, hypertension, diabetes, or preexisting cardiovascular disease or respiratory conditions.
Patients who were overweight had a 22% increased risk of needing invasive (mechanical) ventilation, and those with obesity had a 73% increased risk of this, after multivariable adjustment.
Being overweight or having obesity was not associated with a significantly increased risk of dying in the hospital, however.
“In other viral respiratory infections, such as influenza, there is a similar pattern of increased requirement for ventilatory support but lower in-hospital mortality among individuals with obesity, when compared to those with normal range BMI,” Dr. Longmore noted. She said that larger studies are needed to further explore this finding regarding COVID-19.
Compared to patients without diabetes, those with diabetes had a 21% increased risk of requiring invasive ventilation, but they did not have an increased risk of needing noninvasive ventilation or of dying in the hospital.
As in previous studies, individuals who had cardiovascular and preexisting respiratory diseases were not at greater risk of needing oxygen or mechanical ventilation but were at increased risk for in-hospital death. Men had a greater risk of needing invasive mechanical ventilation, and individuals who were older than 65 had an increased risk of requiring oxygen or of dying in the hospital.
A living meta-analysis, call for more collaborators
“We consider this a ‘living meta-analysis’ and invite other centers to join us,” Dr. Longmore said. “We hope to update the analyses as more data are contributed.”
No specific project funded the study. The authors have disclosed no relevant financial relationships.
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