Inclusion Criteria:  age ranges from 18 to 100 years old Signed informed consent and agreed to participate in this study The diagnosis of T2DM is based on standard criteria recommended by WHO since 1999 The diagnosis of T2DM patient with LEAD is based on standard criteria recommended by Chinese guideline on prevention and management of diabetic foot (2019 edition)(II).  Exclusion Criteria:  younger than 18 years old or older than 100 years old acute infection during the preceding 3 months drugs or alcohol addicts cancer type 1 diabetes patients with mental abnormality who are uncooperative with this study pregnant or lactating women refuse to sign informed consent