The goal of this longitudinal observational study is to estimate the performances of a candidate proteomic biomarker to identify patients at short term risk of chronic kidney disease (CKD) progression, in CKD patients attending nephrology visits in 3 participating centres. The primary endpoint of CKD progression is defined as a relative change in eGFR observed at 1 year below -10%. The performance of the candidate biomarker will be compared to performances of UAE and KFRE equations.

Participants will attend two study visits (baseline and 1-year), with clinical evaluation including kidney parameters (eGFR, urinary albumin excretion (UAE)) and collection of biological samples (plasma, serum, urine) for candidate proteomic biomarker evaluation. If planned in routine, patients will also have creatinine clearance estimation from 24-hour urine collection, kidney echography and kidney biopsy, sample biobanking and/or questionnaires and interviews on social and ethical aspects.

Inclusion Criteria:

• Male or female patients
• over 18 years and below 85 years of age at recruitment
• Chronic kidney disease (CKD)
• eGFR of 25-65 mL/min/1.73m2 (CKD-EPI formula)
• Beneficiary of health insurance
• Must be able to communicate with the investigator
• Written informed consent must be provided before participation.

Exclusion Criteria:

• History of renal transplantation
• Current episode of Acute Kidney Injury
• Any clinically significant disorder, which in the Investigator's opinion could interfere with the results of the trial.
• Known or suspected abuse of alcohol or narcotics
• Current pregnancy
• Inability to give written informed consent
• Protected adults

CKD patients attending nephrology medical visits