Abstract
Aging is an inevitable process that is usually measured by chronological age, with people aged 65 and over being defined as "older individuals". There is disagreement in the current scientific literature regarding the best methods to estimate glomerular filtration rate (eGFR) in older adults. Several studies suggest the use of an age-adjusted definition to improve accuracy and avoid overdiagnosis. In contrast, some researchers argue that such changes could complicate the classification of chronic kidney disease (CKD). Several formulas, including the Modification of Diet in Renal Disease, CKD-Epidemiology Collaboration, and Cockcroft-Gault equations, are used to estimate eGFR. However, each of these formulas has significant limitations when applied to older adults, primarily due to sarcopenia and malnutrition, which greatly affect both muscle mass and creatinine levels. Alternative formulas, such as the Berlin Initiative Study and the Full Age Spectrum equations, provide more accurate estimates of values for older adults by accounting for age-related physiological changes. In frail older adults, the use of cystatin C leads to better eGFR calculations to assess renal function. Accurate eGFR measurements improve the health of older patients by enabling better medication dosing. A thorough approach that includes multiple calibrated diagnostic methods and a detailed geriatric assessment is necessary for the effective management of kidney disease and other age-related conditions in older adults.