Median plasma leptin level in COVID-19 patients living 30 days after ICU admission was 20.3 ng × mL−1 (IQR = (Q3–Q1) = 32.1), whereas those who died within 30 days after ICU admission had median plasma leptin level at 16.7 ng × mL−1 (IQR = (Q3–Q1) = 23.6) (n.s.). The gene discussed is LEP; the disease is COVID-19.