Chronic kidney disease has become an important Public Health issue in most developed and developing countries, with increasing incidence and prevalence rates. The cost associated with chronic kidney disease patients is very high, derived from renal replacement therapy and the cost associated with the high cardiovascular risk of this population. Primary and secondary preventive measures are imperative. In this sense, the comprehension of mechanisms and biomarkers associated with CKD progression and mortality risk in this population is an important area of research. Cohort studies are important tools for testing risk factors and biomarkers. Currently, CKD cohorts, particularly of those not on dialysis, are few and restricted to North America and Europe.

The present study established a cohort of 454 CKD participants (not on dialysis) in Sao Paulo, Brazil, who will be followed for 7-10 years. Baseline data collection was wide, including medical history, diet (food frequency questionnaire), calcium score, echocardiography, pulse wave velocity, cardiac frequency variability, carotid intimal media thickness, retinography, and an extensive biobank. Follow-up is ongoing and made through annual telephone interviews including questions on death, hospitalizations, and need of renal replacement therapy (RRT). Vital status is investigated periodically by a hot-pursuit strategy.

Inclusion Criteria:

• Patients attending the outpatient service of Hospital das Clínicas, São Paulo, Brazil.
• ≥ 30 years.
• at least two measurements of creatinine (with a minimum interval of 3 months) ≥ 1.6 mg/dl for men and ≥ 1.4 mg/ dl for women.

Exclusion Criteria:

• Patients attending oncology, psychiatry, human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS), viral hepatitis and glomerulonephritis services were excluded.
• hospitalization within the last six months;
• acute myocardial infarction within the last six months;
• autoimmune diseases;
• current pregnancy;
• psychiatric diseases;
• ongoing chemotherapy or immunosuppressive therapy;
• current renal replacement therapy;
• HIV/AIDS infection;
• hepatitis B or C;
• any organ transplantation.

Patients attending the outpatient service of Hospital das Clínicas, São Paulo, a public university facility providing quaternary-level care for patients with chronic diseases, were invited to participate in this study. Initially, from the outpatient records, all patients aged

≥ 30 years and at least two measurements of creatinine (with a minimum interval of 3 months) ≥ 1.6 mg/dl for men and ≥ 1.4 mg/ dl for women were considered potential candidates. Patients attending oncology, psychiatry, human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS), viral hepatitis and glomerulonephritis services were excluded. The remaining candidates were then contacted by phone and were invited to participate if they did not meet any exclusion criteria.