Is CKD a normal part of aging? Understanding the difference

While it is a fact that kidney function naturally declines with age, chronic kidney disease (CKD) is not a normal or inevitable part of aging. A 2024 study noted that roughly a third of people aged 70 or older have CKD, but this high prevalence does not equate to it being a normal physiological process. Understanding this critical distinction is key for older adults and their caregivers to take proactive steps toward kidney health.

Quick Summary

This article explores the difference between normal age-related kidney decline and chronic kidney disease, highlighting key diagnostic differences and risk factors. It details the structural and functional changes that occur during physiological aging versus the accelerated damage caused by CKD. The piece also provides information on managing risk factors and when to seek medical evaluation for better long-term kidney health.

Key Points

• CKD is Not Normal Aging: While kidney function declines with age, chronic kidney disease (CKD) is a separate, pathological condition that involves accelerated, irreversible damage.

• Albuminuria is a Key Marker: Unlike healthy aging, a hallmark of CKD is the presence of protein (albuminuria) in the urine, even with only a mild reduction in filtration rate.

• Comorbidities are Major Drivers: The high prevalence of CKD in older adults is largely due to age-related increases in risk factors such as diabetes, high blood pressure, and cardiovascular disease.

• Regular Screening is Vital: Given that early CKD often has no symptoms, the National Kidney Foundation recommends annual screening for individuals over 60, particularly those with other risk factors.

• Preventative Lifestyles Help: Managing blood pressure and diabetes, maintaining a healthy weight, exercising, and avoiding smoking are critical steps to prevent or slow the progression of CKD.

• Distinction is Crucial for Treatment: Differentiating between normal age-related changes and actual kidney disease helps clinicians avoid over-diagnosing healthy seniors and ensures that those with genuine CKD get appropriate management.

Normal age-related kidney decline vs. chronic kidney disease (CKD)

While reduced kidney function is common in older populations, chronic kidney disease (CKD) is not considered a normal part of aging. Normal aging of the kidneys involves a gradual decrease in filtering capacity, typically without signs of kidney damage like protein in the urine (albuminuria). CKD, conversely, is a disease marked by accelerated, irreversible damage and a more rapid decline in function over time.

As kidneys age normally, their mass and blood flow diminish, leading to a slow reduction in glomerular filtration rate (GFR). This process usually doesn't cause kidney failure in otherwise healthy individuals. CKD, however, is a progressive condition often worsened by other health issues common in older adults, such as diabetes and high blood pressure.

The pathological hallmarks of chronic kidney disease

CKD is often seen as a state of accelerated kidney aging, involving faster cellular senescence and chronic inflammation. While mild inflammation can occur with normal aging, it is more severe and damaging in CKD.

Key differences in kidney pathology include:

• Nephron loss: Loss of kidney filtering units (nephrons) happens in both, but is much more severe in CKD.
• Glomerular sclerosis: Scarring of glomeruli is minimal in healthy aging but widespread and destructive in CKD.
• Fibrosis: Significant scar tissue formation in the kidney (tubulointerstitial fibrosis) is characteristic of CKD, not healthy aging.
• Albuminuria: The presence of albuminuria is a key indicator of kidney damage and a defining feature of CKD, which is absent in healthy aging.

Risk factors for CKD beyond age

Age increases CKD risk, but it's not the only factor. Many conditions and lifestyle choices contribute to CKD. Distinguishing between normal age-related decline and disease is a challenge in older adults.

Major risk factors include:

• Diabetes: High blood sugar harms kidney blood vessels.
• High Blood Pressure: A primary driver of kidney disease.
• Heart Disease/Stroke: Increases risk of kidney damage.
• Obesity: Adds stress to the kidneys.
• Family History: Genetic factors can play a role.
• Smoking: Damages blood vessels, including in the kidneys.
• Acute Kidney Injury (AKI): A history of AKI increases the likelihood of developing CKD later.

Comparison: Age-Related Kidney Decline vs. CKD

Feature	Normal Age-Related Decline	Chronic Kidney Disease (CKD)
Onset	Gradual, predictable decline over decades, starting around age 40.	Progressive and accelerated decline, often linked to comorbidities like diabetes or hypertension.
Primary Cause	Physiological processes, including reduced renal blood flow and gradual nephron loss.	Underlying diseases or damage (e.g., diabetes, hypertension, glomerulonephritis).
Albuminuria	Not typically present in healthy aging.	A primary marker of kidney damage and a key diagnostic indicator.
Sclerosis	Mild increase in global glomerulosclerosis, but minimal interstitial fibrosis.	Widespread glomerular sclerosis and significant interstitial fibrosis.
Progression to ESRD	Unlikely to progress to end-stage renal disease (ESRD) in the absence of other risk factors.	Increased risk of progressing to ESRD, especially in severe stages.
Associated Risks	Lowered physiological reserve and higher susceptibility to AKI.	Increased risk of cardiovascular events, anemia, bone disease, and frailty.

Management strategies and preventative measures

Older adults can take steps to manage risk factors and co-existing conditions to slow or prevent CKD progression. While aging is inevitable, accelerated kidney damage is not.

Lifestyle interventions:

• Control blood pressure.
• Manage diabetes.
• Eat a heart-healthy diet.
• Exercise regularly.
• Quit smoking.
• Maintain a healthy weight.

Medical surveillance:

• Regular screenings: Recommended annually for those over 60, especially with diabetes, high blood pressure, or family history. Screening includes blood tests for eGFR and urine tests for albuminuria.
• Careful medication use: Avoid frequent use of NSAIDs like ibuprofen, which can harm kidneys, particularly in older adults.

Conclusion

Chronic kidney disease is a pathological condition distinct from the mild, natural decline in kidney function that occurs with aging. The high incidence of CKD in older individuals is mainly due to risk factors like high blood pressure and diabetes. Recognizing the difference and managing these factors can significantly improve kidney health in older adults and reduce the risk of kidney failure. Regular screening is essential for early detection and treatment.

Frequently Asked Questions

Is it true that everyone gets CKD eventually if they live long enough?

No, this is a misconception. While it is true that a mild reduction in kidney function is a normal part of aging, chronic kidney disease is a specific condition caused by lasting kidney damage, often from other health issues like diabetes or high blood pressure. A healthy older adult without these risk factors is not expected to develop CKD leading to kidney failure.

What is the key difference between age-related kidney decline and CKD?

The key difference lies in the presence of kidney damage. Normal age-related decline is a slow, physiological process in which the kidneys' filtering capacity diminishes gradually. CKD is characterized by actual structural damage to the kidneys, often indicated by markers like albumin (protein) in the urine.

If my GFR is below 60, does that mean I have CKD?

Not necessarily. While an estimated glomerular filtration rate (eGFR) below 60 mL/min/1.73 m2 for more than three months is a criterion for CKD, it must be considered alongside other factors, such as albuminuria. Some experts argue that an age-adapted eGFR threshold should be used to avoid over-diagnosing healthy elderly people whose eGFR naturally declines.

What symptoms should an older person watch for that might indicate CKD?

Early CKD often has no symptoms. In later stages, signs may include fatigue, swollen ankles or feet, dry/itchy skin, muscle cramps, a need to urinate more often (especially at night), and changes in urine appearance. These symptoms can be subtle and overlap with other conditions, so regular screening is important.

Can lifestyle changes prevent CKD in older age?

Yes, absolutely. Adopting a healthy lifestyle is a cornerstone of preventing CKD. This includes managing underlying conditions like high blood pressure and diabetes, maintaining a healthy weight, eating a low-sodium diet, exercising regularly, and not smoking.

How do doctors tell the difference between normal aging and true CKD?

Doctors use several tests to distinguish the two. A routine blood test measures creatinine to estimate GFR, and a urine test checks for albumin (protein). The presence of albuminuria, combined with a consistently low eGFR over time, is a key indicator of true kidney damage and not just age-related decline.

Is it safe for older adults to take over-the-counter pain medications like ibuprofen?

Regular and long-term use of NSAIDs like ibuprofen can be harmful to the kidneys, particularly in older adults with pre-existing kidney issues or who are dehydrated. It is crucial to use these medications sparingly and consult a doctor for pain management advice.