The document discusses how aging impacts the kidneys. As people age, their kidneys undergo structural and functional changes such as loss of mass and function, granularity on the external surface, and thickening of arteries. The prevalence of conditions like diabetes, hypertension, and high cholesterol increase with age and contribute to declining kidney function. Studies show that while chronic kidney disease risk increases with age, elderly patients are less likely than younger patients to progress to end-stage renal disease, though a subset will eventually need renal replacement therapy. Nephrologists face the challenge of identifying older patients with declining kidney function who would benefit from interventions to slow progression.