According to Egger’s test, there was a suggestion of publication bias for the association of obesity, blood glucose per unit increase at admission and unspecified chronic obstructive diseases with COVID-19-related death, as well as for the association of overweight, obesity, blood glucose per unit increase at admission, use of thiazolidinediones, CKD, unspecified chronic pulmonary diseases, CRP level and lymphocyte count with COVID-19 severity, and the funnel plots show that studies with null or negative findings were missing (ESM Figs. 101, 102, 110, 117, 124, 125, 130 and 132). This evidence concerns the gene CRP and chronic kidney disease.