Are currently GFR estimating equations and standard Kt/V value adequate for advanced chronic kidney disease (CKD) frail elderly patients?

Chronic kidney disease (CKD) elderly patients have a reduced glomerular filtration rate (GFR) due to the combination of ageing and chronic nephropathy damage. This situation is very important to be taken into account in order to prescribe an adequate medication and dialysis dose in this aged group. Besides, cognitive and urinary incontinence problems make difficult to obtain an adequate 24-h urine collection in order to evaluate creatinine clearance in this group. Thus, a reliable GFR estimating equation would be very useful for assisting elderly CKD patients. Additionally, Kt/V is the main parameter currently used for dosing dialysis in stage V CKD young and elderly patients. However, frailty and sarcopenia are prevalent disorders usually suffered by old people, who also present many physiological changes that could make GFR estimating equations and standard Kt/V value to become unreliable in this particular group. In conclusion, based on all these facts, it seems crucial for clinical geriatric nephrology to carefully evaluate how reliable current GFR estimating equations are, as well as which would be an adequate Kt/V value in CKD frail elderly patients.