Kaplan–Meier curves showed that a higher risk of all-cause mortality in patients with COVID-19 and T2DM might be caused by the inhospital use of insulin; however, the use of metformin and AGIs performed a lower risk (p < 0.001), consistent with our above results (Fig. 3a–c and Fig. S2a–c). The gene discussed is INS; the disease is type 2 diabetes mellitus.