Obesity has been recognised as a risk factor for severe Covid-19, increasing the risk of hospitalization, admission to the intensive care unit and death. Higher the body mass index (BMI), greater the risk. however, a recently published study from Wuhan has suggested that it’s not just the overweight and the obese, the underweight individuals too are at risk of severe Covid-19.

The single-center retrospective cohort study published in the journal Frontiers in Nutrition included 193 patients with RTPCR confirmed Covid-19. Data January 1, 2020 to March 13, 2020 was obtained from the hospital. They were followed up until April 15, 2020. The BMI of the patients was calculated; BMI <18 kg/m2 was considered as underweight; BMI ranging from 24.0 to 27.9 kg/m2 was defined as overweight, while BMI 28 kg/m2 was considered as obesity. Normal BMI was defined as 18.5-23.9 kg/m2.

Out of the 193 patients, 58.03% were normal weight, 5.70% were underweight, 27.98% were overweight, while 8.29% were found to be obese.

Lymphopenia, raised CRP, bilateral multiple mottling, and ground glass opacity in the lungs were more commonly observed in the obese. The obese patients were also more likely to have been treated with human immunoglobulin + systematic corticosteroids treatment. Underweight patients were more likely to have a headache. Secondary infections were also 3.255 times more common in the underweight patients than in the obese patients.

Both underweight and obese Covid-19 patients were at risk of developing acute liver injury. Compared to the normal weight patients, the risk of developing acute lung injury was 6.483-fold higher in the underweight group. The risk was 5.965 higher in the obese patients.

This study shows that the underweight Covid-19 patients too are at risk of developing severe disease. The authors suggest that BMI should be taken into account when assessing risk of the patient and deciding the line of management.

Reference

1. Ye P, et al. Both underweight and obesity are associated with an increased risk of coronavirus disease 2019 (COVID-19) severity. Front Nutr. 2021 Oct 8;8:649422.