Preserving kidney function and improving the transition from CKD to End stage renal disease (ESRD) is a research and healthcare challenge. The Chronic Kidney Disease-Renal Epidemiology and Information Network (CKD-REIN) cohort was established to identify the determinants, biomarkers and practice patterns associated with chronic kidney disease outcomes. The study includes 3,033 adult patients with moderate to advanced CKD from a representative sample of 40 nephrology clinics in France with respect to regions and legal status. Patients are recruited during a routine visit and followed up for 5 years, before and after starting renal replacement therapy. Patient-level clinical, biological, and lifestyle data are collected annually, as well as provider-level data on clinical practices, coordinated with the International Chronic Kidney Disease Outcomes and Practice Pattern Study (CKDopps). Blood and urine samples are stored in a biobank. The overall objective is to develop a research platform to address key questions regarding the determinants and biomarkers associated with adverse outcomes in CKD and to assess its effective management. It has the following hypotheses and specific aims:

1. to evaluate a large set of social, environmental, bioclinical, and genetic factors, and their interactions in relation with CKD outcomes including progression to ESRD, mortality, metabolic and vascular complications, and the onset of a number of chronic and acute events;
2. to assess several new biomarkers to predict adverse outcomes of CKD and its complications;
3. to evaluate the associations of provider practices (management of hypertension, anemia, nutritional abnormalities, mineral and bone disorder, nutritional status, timing of dialysis initiation and transplant wait-listing) with achievement of clinical practice guidelines, clinical and patient-reported outcomes (PRO).
4. to evaluate the associations of health care organization and clinic services (e.g., for nutrition, educational programs) with clinical and patient-reported outcomes, and achievement of clinical practice guidelines;
5. to estimate the relative cost-effectiveness of different provider practices and clinic services.

All cohort participants are assessed annually for at least 5 years, until 6 months after the start of renal replacement therapy.

Each year, data are collected from both medical records and patients interview and self-administrated questionnaires are asked to report clinical events.

Interviews and routine biological measurements are repeated annually.

CKD-REIN is funded by the Agence Nationale de la Recherche through the 2010 'Cohortes-Investissements d'Avenir' programme and by the 2010 national Programme Hospitalier de Recherche Clinique.

CKD-REIN is also supported through a public-private partnership with Amgen, Fresenius Medical Care, and GlaxoSmithKline since 2012; Baxter and MerckSharp&Dohme-Chibret (France) from 2012 to 2017; LillyFrance since 2013; Otsuka Pharmaceutical since 2015; Vifor Fresenius since 2017; AstraZeneca since 2018; and Sanofi-Genzyme from 2012 to 2015.

Inclusion Criteria:

• eGFR < 60 ml/min/1.73m2 for at least 1 month
• no prior chronic dialysis or transplantation
• Written Signed consent form

Exclusion Criteria:

• Age <18 yrs old,
• Pregnant female,
• patients who plan to move
• Unable to give inform consent,
• Decline to participate

Patients with CKD Stage 3-5 (eGFR <60 ml/min/1.73m2, not on dialysis or with kidney transplant) receiving nephrology care