Ageing meets kidney disease

Abstract

Chronic kidney disease (CKD) is defined as abnormalities of kidney structure or function, present for ˃3 months, with implications for health. The most used diagnostic criteria are a urinary albumin: creatinine ratio ≥30 mg/g or an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m². Either of these diagnostic thresholds is associated with adverse health outcomes. GFR decreases with age and the prevalence of CKD is highest in older adults; moreover, the presence of CKD is associated with an increased risk of all-cause and cardiovascular death related to accelerated ageing in all age ranges, and the absolute increase in risk is highest for those aged ˃75 years. Indeed, premature death is a more common outcome than CKD progression to kidney failure requiring kidney replacement therapy. The progressive ageing of the world population contributes to the projection that CKD will become the second most common cause of death before the end of the century in countries with long life expectancy. The current collection of selected studies on kidney disease and ageing published in Age&Ageing, NDT and CKJ provides an overview of key topics, including cognitive decline, sarcopaenia, wasting and cardiovascular and non-cardiovascular morbidity and mortality, the management of kidney failure and gender differences in CKD progression.

Keywords: ageing; chronic kidney disease; cognitive decline; haemodialysis; sarcopaenia; transplantation.

FIGURE 1:

Interaction between ageing and kidney disease. Chronological ageing is associated to a progressive decrease of multiple kidney functions, including glomerular filtration. While the age-associated decrease in eGFR has been considered ‘physiological’ by some, when it reaches the threshold values to diagnose chronic kidney disease (CKD), it is associated with adverse outcomes, including increased mortality, and should no longer be viewed as ‘physiological’, in the same manner that the age-associated development of hypertension is not considered ‘physiological’. Both ageing and CKD are risk factors for acute kidney injury (AKI) and AKI may accelerate CKD progression. Through multiple mechanisms, CKD accelerates biological ageing.