This longitudinal cohort study will follow 2500 prevalent Chronic Kidney Disease (CKD)patients under the care of a nephrologist at 3 Southern Ontario Nephrology centres and all affiliated satellite centres with an estimated Glomerular Filtration Rate (eGFR) less than 60 ml/min to determine the rate of their renal disease progression over a 36 months. All CKD patients older than 18 years of age may be included in this study. This study will analyze, with 6 month serial measurements, conventional biochemical, hormonal and metabolic parameters in addition to the demographics, clinical status, medications and blood and urine samples of these patients. This study will assess the influence of inflammation on FGF23 and genetic polymorphisms that may reflect the processes involved with disease progression.