[Evaluation of kidney function in older adults]

The evaluation of renal function in older adults is usually carried out with a creatinine clearance or an estimation of glomerular filtration rate using formulas such as Cockcroft-Gault, MDRD or CKD-EPI. The results obtained with these formulas are often regarded as equivalent. However, in adults older than 70 years, the Cockcroft-Gault formula frequently underestimates the glomerular filtration rate with respect to reference methods and the MDRD formula overestimates it. CKD-EPI has a more unpredictable behavior. This leads to erroneously classifying patients in the stages of chronic kidney disease (CKD), artificially increasing the prevalence of this condition, overloading health systems and generating emotional disorders in patients mistakenly classified as carriers of CKD. Also, when kidney function is overestimated, CKD patients are prevented from receiving the treatments appropriate for their condition. In recent years, new formulas have been proposed (FAS, BIS) with a greater accuracy to estimate glomerular filtration rate in older adults. This review describes the behavior of these formulas in a significant number of older adults, from various countries, and proposes using those equations with the best performance in older adults.