Therefore, we collated mortality data for patients with DFU collected from the National Health and Nutrition Examination Survey (NHANES) population database during 1994-2004, as well as three indices of renal function, including albumin creatinine ratio (ACR), estimated glomerular filtration rate (eGFR), and cystatin C, which is used in the assessment of chronic kidney disease (CKD), to explore the relationship between CKD and the risk of death in patients with DFU. Here, CST3 is linked to chronic kidney disease.