BMI does not dictate COVID-19 disease course

Body mass index (BMI) does not appear to have any relevant influence on the immunological response or outcomes of COVID-19, according to a study.

The analysis included 67 COVID-19 patients admitted in the intensive care unit (ICU). Of these, 18 patients were obese (BMI ≥30 kg/m²; 72 percent with class I and 28 percent with class II obesity) and 49 were not (BMI <30 kg/m²).

All patients had their circulating levels of interleukin (IL)-6, IL-8, IL-10, tumour necrosis factor alpha (TNF-α), interferon gamma (IFN-γ), interferon gamma-induced protein (IP)-10, monocyte chemoattractant protein (MCP)-1, and IL-1 receptor antagonist (RA) monitored from ICU admission until 10 days afterward. Their routine laboratory and clinical parameters were also collected.

Median BMI was 32.6 kg/m² in the obese group and 26.0 kg/m² in the nonobese group. Clinical characteristics on ICU admission did not differ between the two groups, with the exception of temperature, which was significantly lower in obese patients (median, 38.1 [36.9–38.9] vs 38.7 [38.0 −39.5] °C; p=0.02).

Plasma cytokine concentrations declined over time (p<0.05 for all), although there were no differences seen between the obese and nonobese groups. Furthermore, BMI showed no association with the cytokine response (IL-6, p=0.61; TNF-α, p=0.99; IP-10, p=0.11). The kinetics of clinical inflammatory parameters and respiratory mechanics were also comparable in both groups.

Compared with nonobese patients, those with obesity had similar time on ventilator, ICU length of stay, and 40-day mortality.

A larger multicentre study with a more expansive BMI distribution is needed to validate the present data.