INS and diabetes mellitus: Above all, diabetes is associated with increased incidence and severity of COVID-19, and more intensive attention should be paid to diabetes patients in order to prevent rapid deterioration, since hypoxemia and abnormal liver and kidney functions exist in most COVID-19 patients, oral hypoglycemic drugs (especially biguanidine) should not be administered, while insulin injection, intravenous drips, or insulin pumps are recommended to be used frequently.