Even mild obesity raises severe COVID-19 risks

People with a body mass index of 30 kg/m² or above are at significantly increased risk for severe COVID-19, while a BMI of 35 and higher dramatically increases the risk for death, new research suggests.

The data, from nearly 500 patients hospitalized with COVID-19 in March and April 2020, were published in the European Journal of Endocrinology by Matteo Rottoli, MD, of the Alma Mater Studiorum, University of Bologna (Italy), and colleagues.

The data support the recent change by the Centers for Disease Control and Prevention to lower the cutoff for categorizing a person at increased risk from COVID-19 from a BMI of 40 down to 30. However, in the United Kingdom, the National Health Service still lists only a BMI of 40 or above as placing a person at “moderate risk (clinically vulnerable).”

“This finding calls for prevention and treatment strategies to reduce the risk of infection and hospitalization in patients with relevant degrees of obesity, supporting a revision of the BMI cutoff of 40 kg/m², which was proposed as an independent risk factor for an adverse outcome of COVID-19 in the … guidelines for social distancing in the United Kingdom: It may be appropriate to include patients with BMI >30 among those at higher risk for COVID-19 severe progression,” the authors wrote.

The study included 482 adults admitted with confirmed COVID-19 to a single Italian hospital between March 1 and April 20, 2020. Of those, 41.9% had a BMI of less than 25 (normal weight), 36.5% had a BMI of 25-29.9 (overweight), and 21.6% had BMI of at least 30 (obese). Of the obese group, 20 (4.1%) had BMIs of at least 35, while 18 patients (3.7%) had BMIs of less than 20 (underweight).

Among those with obesity, 51.9% experienced respiratory failure, 36.4% were admitted to the ICU, 25% required mechanical ventilation, and 29.8% died within 30 days of symptom onset.

Patients with BMIs of at least 30 had significantly increased risks for respiratory failure (odds ratio, 2.48; P = .001), ICU admission (OR, 5.28; P < .001), and death (2.35, P = .017), compared with those with lower BMIs. Within the group classified as obese, the risks of respiratory failure and ICU admission were higher, with BMIs of 30-34.9 (OR, 2.32; P = .004 and OR, 4.96; P < .001, respectively) and for BMIs of at least 35 (OR, 3.24; P = .019 and OR, 6.58; P < .001, respectively).

The risk of death was significantly higher among patients with a BMI of at least 35 (OR, 12.1; P < .001).

Every 1-unit increase in BMI was significantly associated with all outcomes, but there was no significant difference in any outcome between the 25-29.9 BMI category and normal weight. In all models, the BMI cutoff for increased risk was 30.

The authors reported no disclosures.

SOURCE: Rottoli M et al. Eur J Endocrinol. 2020 Jul 1. doi: 10.1530/EJE-20-054.