A further systematic review and meta-analysis of ten studies with 7012 COVID-19 patients with diabetes reported that there was no association between DPP4 inhibitors and severe COVID-19 (OR 1.07; 95% CI 0.87, 1.31) or mortality (OR 1.14; 0.87, 1.51) [17]. This evidence concerns the gene DPP4 and diabetes mellitus.