Assessment of renal function in elderly patients.

PURPOSE OF REVIEW: The proportion of elderly individuals is growing rapidly in all societies and the incidence of chronic kidney disease among elderly people increases constantly. Accurate monitoring of kidney function, that is, glomerular filtration rate, in elderly people is therefore of considerable clinical interest in order to detect individuals who are at risk for developing chronic kidney disease. This paper reviews the currently used methods for assessment of glomerular filtration rate and their utility in elderly people. RECENT
FINDINGS: Serum creatinine is an unreliable indicator of glomerular filtration rate in elderly people, particularly in those who are sick or malnourished or both. Thus, more reliable glomerular filtration rate estimates should be employed whenever indicated, for example, timed creatinine clearance, serum creatinine-based equations such as the Modification of Diet in Renal Disease formula, or serum cystatin C. However, no single method may be satisfactory.
SUMMARY: Accurate assessment of renal function is a prerequisite for the correct management of elderly people at risk of developing chronic kidney disease; for example, those with diabetes, hypertension, and other clinical conditions that may considerably accelerate an age-related decrease in glomerular filtration rate. The Modification of Diet in Renal Disease formula should be used in most cases, but serum cystatin C or even an isotope clearance method may be helpful if there is concern about the reliability of the Modification of Diet in Renal Disease equation in an elderly individual in whom precise assessment of kidney function is mandatory.