No abstract

The MDRD equation systematically underestimates GFR in healthy persons. A new equation developed with patients who have chronic kidney disease and healthy persons may be a step toward accurately estimating GFR when the diagnosis of chronic kidney disease is unknown.

Senescence or normal physiologic aging portrays the expected age-related changes in the kidney as compared to a disease that occurs in some but not all individuals. The micro-anatomical structural changes of the kidney with older age include a decreased number of functional glomeruli from an increased prevalence of nephrosclerosis (arteriosclerosis, glomerulosclerosis, and tubular atrophy with interstitial fibrosis), and to some extent, compensatory hypertrophy of remaining nephrons. Among the macro-anatomical structural changes, older age associates with smaller cortical volume, larger medullary volume until middle age, and larger and more numerous renal cysts. Among carefully-screened healthy kidney donors, glomerular filtration rate declines at a rate of 6.3 ml/min/1.73m2 per decade. There is reason to be concerned that the elderly are being misdiagnosed with chronic kidney disease. Besides this expected kidney function decline, the lowest risk of mortality is at a glomerular filtration rate of ≥75 ml/min/1.73 m2 for age <55 years but at a lower glomerular filtration rate of 45-104 ml/min/1.73m2 for age ≥65 years. Changes with normal aging are still of clinical significance. The elderly have less renal functional reserve when they do actually develop chronic kidney disease and they are also at higher risk for acute kidney injury.

Background-Chronic kidney disease becomes common with age and is characterized on renal biopsy by global glomerulosclerosis, tubular atrophy, interstitial fibrosis, and arteriosclerosis.