Kidney function in older people: pathology, assessment and management.

It is commonly not appreciated that kidney failure is predominantly a disease of older people and that the use of renal replacement therapy (RRT) amongst these patients is increasing rapidly. It is still unclear whether the decline in kidney function with increasing age represents pathology or is part of the normal ageing process. Conventional laboratory approaches to the assessment of kidney function in older people are inadequate, but the use of calculated clearance formulae and serum cystatin C can enable the earlier detection of chronic kidney disease (CKD) in this population. This could facilitate treatment aimed at reducing the progression of kidney disease in older people and improved management of its secondary complications.