Chronic kidney disease (CKD) is a public health problem and affects about 10% of the world's adult population with a constantly increasing incidence. The approach to CKD in France is centered on access to replacement therapy (dialysis, renal transplantation), the cost of which amounts to 4 billion euros (data from the REIN registry). Real-life data are essential to specify the characteristics of patients with chronic kidney disease and the factors associated with the evolution of CKD and the occurrence of complications in order to improve the management of CKD before the suppletion stage. Since October 2019, CKD at the severe stage (stage 4) and at the non-dialysis end stage (stage 5) is subject to an annual flat fee (Article L. 162-22-6-2 of the Social Security Code). The reimbursement of these lump sums by the health insurance is subject to the collection and transmission of certain medical data by the establishments.