The kidney has many important regulatory functions, such as regulation of body fluid volume, solute dilution and concentration, acid-base balance, and the metabolism and excretion of waste products. The kidney secretes hormones that regulate red blood cell (RBC) production, blood pressure, and calcium homeostasis. Chronic kidney disease (CKD), affects these vital processes, with changes seen throughout all organ systems. The equation used to estimate glomerular filtration rate (GFR) is the four-variable modification of diet in renal disease (MDRD) equation that was not validated in patients older than 70 years, nor in children, pregnant women, diabetics, or Hispanics. As a result, the CKD epidemiology equation (EPI) equation was proposed, utilizing pooled data from both CKD and non-CKD patients. The key to improving care for elderly patients with end-stage renal disease (ESRD) is to realize that they are frail, and deserve the same evaluations for potential interventions as those without kidney disease.