Key unsolved issues in kidney replacement therapy.

Ortiz, Alberto; Sanchez-Niño, Maria Dolores

Chronic kidney disease (CKD) is projected to become the fifth global cause of death by 2040, the second before the end of the century in some countries with long life expectancy (1,2). It is additionally the most common risk factor for lethal coronavirus disease-2019 (COVID-19) and the factor that most increased the risk of death in COVID-19 patients (3). The increased risk of death associated with CKD is observed throughout all CKD stages, from early stages in which glomerular filtration is still preserved (and the risk of premature death is thought to be related to decreased kidney production of protective and anti-aging factors such as Klotho) to advanced CKD in which decreased filtration of so-called uremic toxins is thought to be a key driving force (4, 5). Indeed, it has been known from the first successful therapy of acute kidney injury by hemodialysis that clearing uremic toxins, by replacing glomerular filtration, may be lifesaving (6).