CKD: A Call for an Age-Adapted Definition.

Area of Science:

• Nephrology
• Geriatrics
• Public Health

Background:

• Current chronic kidney disease (CKD) diagnosis relies on persistent kidney damage markers or a glomerular filtration rate (GFR) below 60 ml/min/1.73 m².
• This GFR threshold does not differentiate between kidney disease and normal aging, leading to potential misdiagnosis in older adults.
• Healthy aging is associated with a natural decline in GFR, not indicative of pathological kidney damage.

Purpose of the Study:

• To evaluate the limitations of current CKD diagnostic criteria, particularly the fixed GFR threshold across all age groups.
• To propose the implementation of age-specific GFR thresholds for a more accurate CKD diagnosis.
• To explore the implications of revised CKD diagnostic criteria on patient care and global prevalence estimates.

Main Methods:

• Extensive literature review on GFR changes during healthy aging.
• Analysis of data from living kidney donors to compare GFR in different age groups.
• Examination of findings from large meta-analyses, including the CKD Prognosis Consortium, on GFR and mortality risk across ages.

Main Results:

• Glomerular filtration rate (GFR) naturally declines with healthy aging, without signs of kidney damage or compensatory mechanisms.
• Older living kidney donors exhibit lower predonation GFR compared to younger donors.
• The GFR threshold associated with increased mortality risk varies significantly with age, being higher in younger individuals (<75 ml/min/1.73 m²) and lower in the elderly (<45 ml/min/1.73 m²).

Conclusions:

• Amending the definition of CKD to incorporate age-specific GFR thresholds is recommended.
• Implementing age-adjusted criteria could reduce the overdiagnosis of CKD in the elderly, minimizing inappropriate care and adverse effects.
• Revised criteria may lead to earlier detection of kidney disease in younger populations, enabling timely interventions to prevent progression.