Renal hyperfiltration (RHF) has been associated with mortality in several studies which have estimated glomerular filtration rate (eGFR) with the creatinine-based Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation [1–9]. However, this relationship remains controversial since the pathophysiological mechanisms responsible for the association are not known. Moreover, the definition of RHF has varied between the studies, most of them using an eGFR threshold between 90 and 125 ml/min per 1.73 m2.
