Severe obesity, specifically in men and younger patients, is a high-profile risk factor for adverse outcomes from COVID-19, specifically mortality, according to a study published in Annals of Internal Medicine.  

“Our study contributes to our understanding of the effect of obesity on adverse outcomes associated with COVID-19 in several important ways,” stated the authors. “Although previous studies have primarily focused on risk among the hospitalized population, we present finding that can inform decisions much earlier in the triage process, including in the ambulatory setting.”

Researchers conducted a retrospective study of members of Kaiser Permanente Southern California who were diagnosed with COVID-19 from February 13 to May 2, 2020. The researchers focused on the effect body mass index (BMI) had on mortality within 21 days of COVID-19 diagnosis (index date). BMI was categorized by underweight (<18.5 kg/m2), normal (18.5-24 kg/m2), overweight (25-29 kg/m2), obese class I (30-34 kg/m2), obese class II (35-39 kg/m2), and obese class III or extreme obesity (>40 kg/m2).

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A total of 6916 patients with COVID-19 were identified for the analysis; of these, 5652 (82%) were diagnosed by PCR testing. The majority of patients with COVID-19 were women (55%) and Hispanic (54.2%). At the index date, the mean age of patients was 49.1 years and the mean BMI was 30.6 kg/m2. The most prevalent comorbidities included hypertension (24%), hyperlipidemia (23%), diabetes (20%), and asthma (18%). Approximately 8% of patients were insured by Medicaid.

A total of 206 (3%) patients died within 21 days of their COVID-19 diagnosis, with 67% hospitalized and 43% intubated between the index date and date of death. Of the patients that survived, 15% were hospitalized and 3% were intubated.

Researchers found a J-shaped association between BMI and risk for death, even after adjusting for obesity-related comorbidities. Compared with normal weight patients, those with class III obesity had 2.68 relative risk of morbidity (95% CI, 1.43-5.04). And patients with a BMI >45 kg/m2 were 4 times at risk of dying compared to normal weight patients (95% CI, 2.12 to 8.26).

In age-stratified analyses, among those aged ≤60 years or younger, an increased risk for death with high BMI was found compared with the overall model. For those aged ≥61 years, BMI was associated with death to a much lesser degree and only for the highest measures. Men had a higher risk of death compared with women; women had no increased risk for death associated with BMI.

The study finding that severe obesity, particularly among younger patients, “eclipses the mortality risk posed by other obesity-related conditions, such as history of myocardial infarction, diabetes, hypertension, or hyperlipidemia, suggests a significant pathophysiologic link between excess adiposity and severe COVID-19 illness,” concluded the authors.

Disclosure: This study was funded by Roche-Genentech.


Tartof SY, Qian L, Hong V, et al. Obesity and mortality among patients diagnosed with COVID-19: results from an integrated health care organization. Ann Intern Med. Published online August 12, 2020. doi:10.7326/M20-3742

This article originally appeared on Clinical Advisor