Population ageing will exacerbate the burden of ageing-related diseases, including chronic kidney disease. Mitigating the effects of this burden will require coordinated, multinational efforts.

According to United Nations estimates, people aged ≥65 years will account for >16% of the world’s population by 2050 (ref. 1). Although the effects of population ageing will be felt across societies, the fastest rates of population ageing are predicted to occur in low- and middle-income regions. Given that kidney diseases are associated with both age and socioeconomic factors, these regions are likely to be disproportionally burdened in the future. In this Focus issue, we highlight several issues pertinent to kidney health in the ageing world.

Kidney ageing is characterized by macroscopic and microscopic structural changes. In their Review, Yamamoto and Isaka examine the molecular mechanisms that may underlie these changes2, which provides a framework for understanding the process of kidney ageing. The complexity of the ageing process and heterogeneity in outcomes is highlighted in a Comment from Arai and Yanagita3, who suggest that the study of kidney changes in healthy, older individuals — particularly centenarians — might provide insights into the biological mechanisms that underpin physiological kidney ageing. Interestingly, structural changes seen in aged kidneys are also observed in chronic kidney disease (CKD), which seems to accelerate ageing, creating a discordance between the biological age of the organ and the chronological age of the individual4. This overlap complicates the diagnosis of CKD in older individuals; in their Comment, Rule and Glassock5 consider the limitations of cystatin C and the use of a single threshold for CKD diagnosis regardless of age.

In their Review, Jager and coauthors6 describe potential consequences of the rapidly ageing population for the health and economic burden of CKD. Population ageing will also likely increase the prevalence of risk factors for CKD, including diabetes, hypertension, obesity, cardiovascular disease and acute kidney injury. Moreover, the multimorbidities of CKD — including fatigue, skeletal conditions and cognitive dysfunction — will particularly affect older patients, further increasing the burden of disease in this population. In their Review, Kashihara and colleagues7 outline the considerable challenge for health-care systems posed by population ageing.

Increases in CKD prevalence will lead to an increase in demand for kidney replacement therapies, including dialysis and transplantation. This rise in demand will substantially increase health-care expenditures and exacerbate existing inequities in access to treatment. Fleetwood and Lentine8 note in their Comment that kidneys from older donors are often underutilized, despite acceptable outcomes, especially for age-matched transplantation. They suggest that the diversion of older kidneys to older recipients could lead to reasonable clinical outcomes and improve allocation efficiency. Some patients with kidney failure may choose to forego or discontinue dialysis, and instead receive conservative kidney management (CKM). McMahan and Sudore9 advocate for early initiation of advance care planning — well in advance of major life decisions such as potential dialysis or CKM initiation — and outline strategies to help clinicians to initiate such conversations with their patients.

“The effects of population ageing will be felt across societies”

Population ageing will have far-reaching impacts, with implications for CKD prevalence and health-care resources that could exacerbate existing health inequities. Mitigating these effects will require a redoubling of efforts to coordinate and implement effective disease prevention strategies and ensure widespread and affordable access to kidney-protective drugs, along with further research into the mechanisms of kidney ageing.