Design and methodology of the Aging Nephropathy Study (AGNES): a prospective cohort study of elderly patients with chronic kidney disease.

Background: Renal replacement therapy (RRT) is usually indicated for patients with chronic kidney disease (CKD) with glomerular filtration rate below 10 ml/ml/min/1.73m. However, the need for RRT and timing of dialysis initiation are debatable for patients aged 70 years or older.