Creatinine: What your kidneys can reveal about longevity

Your doctor looks at creatinine in your blood test mainly to estimate kidney filtration. If the value is “within normal range,” it is easy to move on to the next parameter.

Longevity science adds nuance to that routine interpretation. A Swedish study following more than 44,000 people for 35 years found that those who reached 100 tended to have lower creatinine levels than those who did not — but the finding is an association, not proof that lower creatinine is always better.

Creatinine is also one of the 9 biomarkers in PhenoAge, the algorithm developed to estimate biological age from blood tests. Your kidneys, in essence, tell part of the story of how fast your body may be aging.

In this article, I’ll explain why creatinine is much more than a “kidney test,” how to read it without overinterpreting one number, and what you can do to protect kidney function while preserving muscle.

For a lab-report reference page with ranges, aliases, and SuperAge context, see the creatinine and eGFR biomarker guide.

What you’ll learn:

• What creatinine is and why it’s crucial for longevity
• Reference ranges vs. longevity context: the difference that matters
• The science: how kidneys age (and why it matters)
• What centenarians teach us about creatinine
• The role of creatinine in PhenoAge
• 6 evidence-based strategies to optimize creatinine
• How SuperAge tracks creatinine and calculates your biological age
• FAQ

---

Quick answer

Creatinine is a useful longevity marker because it sits at the intersection of kidney filtration and muscle metabolism. Lower values in long-lived cohorts can signal preserved kidney function, but creatinine alone is not a longevity score: low muscle mass can also lower it.

The practical read is trend plus context. Pair creatinine with eGFR, urine albumin-to-creatinine ratio (UACR), cystatin C when muscle mass is unusual, blood pressure, glucose control, medications, and symptoms.

For healthy adults, the goal is not to chase the lowest creatinine. It is to keep kidney function stable, avoid albuminuria, preserve muscle, and prevent the blood-pressure, glucose, and nephrotoxin exposures that accelerate kidney aging.

Key facts

• Creatinine -> kidney-muscle marker: it rises when filtration falls, but it can also rise with higher muscle mass, creatine use, meat intake, or dehydration.
• eGFR -> filtration estimate: it adjusts creatinine for age and sex, but can mislead when muscle mass is unusually high or low.
• Cystatin C -> confirmation marker: KDIGO 2024 supports combined creatinine-cystatin C eGFR when precision matters.
• UACR -> damage signal: albumin in urine can reveal kidney injury even when eGFR is still above 60.
• Trend -> longevity context: stable kidney markers over years matter more than one isolated creatinine value.
• Centenarian data -> association, not destiny: lower creatinine in AMORIS centenarians supports the kidney-longevity link, but it does not prove one target value for every person.

---

What is creatinine?

Creatinine is a waste product of muscle metabolism. When muscles use creatine — a molecule that provides rapid energy during short, intense efforts — the final byproduct is creatinine, which is released into the bloodstream and filtered by the kidneys.

Quick definition: Creatinine is a waste product from muscle creatine, filtered and eliminated by the kidneys. Its level in the blood reflects the kidneys’ ability to filter waste substances — making it one of the most commonly used biomarkers to assess kidney function and, according to recent research, a predictor of aging and longevity.

Why creatinine isn’t “just a kidney indicator”

Creatinine is a dual indicator. On one hand, it reflects kidney function: if the kidneys filter well, blood creatinine stays low. On the other, it’s influenced by muscle mass: the more muscle you have, the more creatinine you produce.

This dual meaning is fundamental to interpreting it correctly:

• High creatinine → Can indicate kidneys not filtering well, or very high muscle mass (bodybuilders, strength athletes)
• Low creatinine → Can indicate efficient kidneys, or reduced muscle mass (sarcopenia, malnutrition)
• Creatinine in context with stable eGFR and UACR → Suggests a healthier balance between muscle production and kidney filtration

Because creatinine alone doesn’t capture the full kidney picture, reading it alongside BUN and the BUN/creatinine ratio adds critical context. The BUN vs creatinine comparison guide explains when each marker is more informative and how to interpret their ratio.

How it’s measured

Creatinine is measured with a simple blood draw (serum creatinine). It’s included in most routine metabolic panels. The value is also used to calculate eGFR (estimated Glomerular Filtration Rate), an estimate of how fast the kidneys filter blood.

---

Reference ranges vs. longevity context: the difference that matters

As with other PhenoAge biomarkers, “within normal range” does not always mean “fully reassuring.” But creatinine is not a marker to minimize at all costs: the right interpretation depends on sex, age, body size, muscle mass, diet, hydration, medications, eGFR, and urine albumin.

Classification	Men (mg/dL)	Women (mg/dL)	What it can mean for aging
Often favorable context	0.8 - 1.0	0.6 - 0.8	Often compatible with preserved filtration, if muscle mass is adequate
Clinical normal	0.7 - 1.3	0.5 - 1.1	“Acceptable” but range too broad
Borderline high	1.3 - 1.5	1.1 - 1.3	Possible reduction in kidney function
High	> 1.5	> 1.3	Likely kidney damage — requires evaluation
Very low	< 0.6	< 0.4	Possible sarcopenia or malnutrition

The crucial difference: a man with creatinine of 1.4 mg/dL may still be close to a lab’s reference range, but his eGFR could be meaningfully lower depending on age and body size. Conversely, a value of 0.5 mg/dL in an older adult could reflect low muscle mass rather than exceptional kidney function.

The creatinine paradox in the elderly

Here’s the problem few doctors explain to patients: with aging, muscle mass decreases (sarcopenia) and kidney filtration rate declines. These two phenomena tend to balance each other out, keeping creatinine apparently stable — even when the kidneys are getting worse.

An elderly person with creatinine of 0.9 mg/dL could have:

• Kidneys still filtering well + preserved muscle mass (favorable scenario)
• Kidneys filtering poorly + very reduced muscle mass (unfavorable scenario)

This is why nephrologists insist on calculating eGFR, which estimates filtration from creatinine plus age and sex. Modern U.S. equations no longer use a race coefficient, and KDIGO 2024 emphasizes adding cystatin C when creatinine-based eGFR may be less accurate.

Age range	Healthy average eGFR (mL/min/1.73m²)	Interpretation
20-30 years	> 100	Full kidney function
40-50 years	90-100	Slight physiological decline
60-70 years	75-90	Moderate but normal decline
80+ years	60-80	Significant reduction
Centenarians	Often lower than young adults	Interpret with muscle mass, albuminuria, and overall health

Key point: Don’t look at creatinine alone. Always ask your doctor for eGFR and, when relevant, UACR. An eGFR below 60 for at least 3 months, or eGFR above 60 with evidence of kidney damage such as albuminuria, can meet criteria for chronic kidney disease.

The 2021 race-free CKD-EPI equation: what changed

Since 2021, the National Kidney Foundation and American Society of Nephrology have supported the race-free CKD-EPI 2021 equation for calculating eGFR, replacing older formulas that included a race coefficient. The creatinine equation uses age, sex, and serum creatinine.

For most patients the eGFR result is similar, but in some cases — particularly at higher eGFR values and in younger adults — values can differ by more than 10% from the older formula. If you compared a recent eGFR to one from before 2022, the number may have shifted without your kidney function actually changing.

The most recent 2024 KDIGO guideline goes one step further: it recommends combining creatinine with cystatin C (a complementary kidney biomarker) for the most accurate kidney function assessment, especially when muscle mass is unusual (very high in athletes, very low in the elderly or sarcopenic patients).

---

The science: how kidneys age (and why it matters)

Kidney decline is one of the first signs of aging

Kidneys often begin losing filtering capacity in adulthood, with many population studies showing a gradual age-related decline in eGFR. The average slope is useful for context, but individual trajectories vary widely. To understand precisely how fast eGFR should decline with age — and when a steeper slope signals accelerated disease — see our dedicated guide on eGFR slope interpretation.

But — and this is the central point — the speed of this decline varies enormously from person to person. Some seventy-year-olds have kidneys that function like those of a fifty-year-old. Others have kidney function of an eighty-year-old. The difference depends on genetics, lifestyle, blood pressure, blood sugar, and other modifiable factors.

Why kidneys are a “sentinel” of aging

Kidneys are extraordinarily complex organs: each kidney contains roughly 1 million nephrons — the functional units that filter blood. With age and injury, the number of functioning nephrons tends to decrease, and the kidney has limited ability to replace lost filtering units.

Kidneys are also the primary source of Klotho, an anti-aging protein hormone that circulates in the blood and regulates phosphate balance, insulin sensitivity, and inflammation. Klotho levels fall sharply with kidney decline — making low Klotho both a consequence and a driver of accelerated systemic aging.

This progressive loss is a miniature model of aging of the entire body. The factors that damage the kidneys are the same ones that accelerate systemic aging:

• Hypertension → Damages the capillaries of nephrons and those throughout the body
• Chronic hyperglycemia → Glycation of kidney proteins and all tissues
• Systemic inflammation → Activates kidney fibrosis and vascular aging
• Oxidative stress → Damages cell membranes of nephrons and all organs

The kidney-aging connection: the data

Research has shown that those who develop chronic kidney disease (CKD) present a profile of accelerated global aging:

• Bone fragility (early osteoporosis)
• Loss of muscle mass (accelerated sarcopenia)
• Greater incidence of cardiovascular events
• Alterations in the immune system
• Predisposition to infections and tumors

In practice, kidneys don’t just filter blood: they’re a window into the overall speed of your body’s aging. When kidneys slow down, risk often rises across several other systems too.

---

What centenarians teach us about creatinine

The AMORIS study: 44,000 people, 35 years of follow-up

The most important study on creatinine and exceptional longevity comes from the Swedish AMORIS cohort (Apolipoprotein MOrtality RISk). Researchers compared blood profiles of those who reached 100 years with those who died earlier, following over 44,000 people for 35 years.

Main result: The differences in average values between centenarians and non-centenarians were especially visible for creatinine and uric acid, but the absolute differences were modest and should not be turned into a universal target.

Centenarians showed:

• Consistently lower creatinine levels compared to non-centenarians
• A homogeneous profile: they rarely had values at the extremes of the range, staying in the low-mid zone
• This pattern was already visible decades before their 100th birthday — suggesting that preserved kidney function may be part of the long-running profile associated with exceptional longevity

The metabolic profile at 65 predicts reaching 100

A particularly significant finding from the AMORIS study: future centenarians had stabilized their metabolic profile by age 65 — a full 35 years before reaching a century.

This means that:

1. At age 65 the trajectory still matters — the profile isn’t fixed at birth
2. Consistency matters more than peaks — you don’t need perfect creatinine once, but to keep it consistently low over time
3. Lower creatinine in centenarians likely reflects a healthier long-term kidney-muscle profile — not a single lucky moment

The muscle-kidney paradox in centenarians

Centenarians usually have less muscle mass than a young person — yet in AMORIS their creatinine tended to be lower. This doesn’t contradict the principle that “more muscle = more creatinine.” Rather, it means creatinine must be read as a kidney-muscle marker, not as a pure kidney score.

In practice, the typical centenarian has:

• Reduced but functional muscle mass (not pathologically sarcopenic)
• Kidneys still filtering well for their age
• Resulting creatinine: lower in context = potentially favorable, if it does not simply reflect severe muscle loss

---

The role of creatinine in PhenoAge

Creatinine among the 9 biomarkers of biological age

PhenoAge, developed by Morgan Levine and colleagues in 2018, uses 9 clinical biomarkers + chronological age to estimate biological age. Creatinine is included as an indicator of kidney function, and its weight in the model reflects the importance of kidneys in predicting mortality.

The 9 PhenoAge biomarkers:

Biomarker	What it measures	Effect on biological age
Albumin	Liver, nutrition, inflammation	↓ albumin → older
Glucose	Metabolism, insulin	↑ glucose → older
Creatinine	Kidney function	↑ creatinine → older
C-reactive protein	Systemic inflammation	↑ CRP → older
White blood cells	Immune system	↑ WBC → older
Lymphocyte %	Adaptive immunity	↓ lymphocytes → older
MCV	Red blood cell size	↑ MCV → older
RDW	Red blood cell variability	↑ RDW → older
Alkaline phosphatase	Liver and bones	↑ ALP → older

Why kidneys matter in PhenoAge

Creatinine was selected from among 42 candidate biomarkers because kidney function is one of the most robust independent predictors of mortality in the general population. It’s not just about kidney disease in the strict sense: even subclinical reductions in filtering capacity — invisible in normal routine tests — are associated with increased cardiovascular risk, cognitive decline, and all-cause mortality.

Genetic studies confirm the connection

Genetic research (GWAS studies) has linked PhenoAge Acceleration — how much biological age exceeds chronological age — with creatinine and cystatin C (another kidney marker), supporting the idea that the kidney-aging connection has biological foundations, not just statistical ones.

The 2025 evidence: a systematic review confirms eGFR predicts mortality in older adults

A 2025 systematic review and meta-analysis published in Kidney Medicine pooled 13 studies and 102,893 participants (mean age 80 years, baseline CKD-EPI eGFR 63 mL/min/1.73m²) to test whether eGFR predicts mortality differently in older adults compared to general-population formulas.

The conclusion: eGFR remains a strong, independent predictor of all-cause mortality in older adults, with no significant performance difference between CKD-EPI 2009/2021 and equations specifically validated for older populations. Notably, cystatin C-based equations showed even stronger associations with mortality than creatinine-based ones — reinforcing the case for combined creatinine + cystatin C assessment (Vega-Cabello et al., 2025).

A separate 2025 study in Journal of Cachexia, Sarcopenia and Muscle introduced the Cystatin C–Creatinine Score: by dividing cystatin C by creatinine, the ratio captures the discrepancy between filtration capacity (cystatin C) and muscle mass (creatinine). A high ratio independently predicts frailty and adverse outcomes in older adults — making it an emerging biomarker for biological aging beyond either marker alone (Deng et al., 2025).

---

6 evidence-based strategies to optimize creatinine

1. Keep blood pressure under control

Why it works: Hypertension is the number 1 cause of chronic kidney damage. High pressure damages the capillaries of kidney glomeruli — the microscopic structures that filter blood. Years of high pressure progressively “consume” nephrons.

How to do it:

• Target: often below 130/80 mmHg for adults with hypertension when tolerated, individualized with your clinician
• Reduce sodium to < 2,300 mg/day (better < 1,500 mg if you already have hypertension)
• Increase potassium with fruits and vegetables (if kidneys function well)
• Regular aerobic exercise: 150 minutes/week at moderate intensity
• Manage chronic stress (reduces cortisol, which raises pressure)

What to expect: Better blood-pressure control is one of the most reliable ways to slow kidney damage risk, especially when hypertension, diabetes, or albuminuria are present.

2. Consistent and adequate hydration

Why it works: Kidneys need adequate blood flow to filter effectively. Chronic dehydration can concentrate waste substances, temporarily raise creatinine, and increase kidney-stone risk.

How to do it:

• Target: 0.5-0.6 oz per lb of body weight per day (30-35 mL/kg). For a 154 lb (70 kg) person, about 71-81 oz (2.1-2.4 liters) per day
• Distribute intake throughout the day, not all at once
• Increase in case of heat, exercise, or high altitude
• Urine is often light yellow when hydration is reasonable, but medications, supplements, and foods can change color
• Limit excessive alcohol and caffeine (both have diuretic effect)

What to expect: Adequate hydration helps avoid false creatinine spikes from dehydration and may reduce kidney-stone risk. More water is not automatically better, especially in heart failure, advanced CKD, or hyponatremia risk.

3. Protein in the right amount (neither too much, nor too little)

Why it works: Proteins are essential for maintaining muscle mass — and sarcopenia is one of the biggest risk factors for mortality in older adults. But in people with CKD, albuminuria, or reduced eGFR, very high protein intake may increase kidney workload and should be individualized.

How to do it:

• Healthy, active adults: often 0.5-0.7 g of protein per lb of body weight per day (1.2-1.6 g/kg), adjusted for age, training, and body composition
• If CKD, albuminuria, or reduced eGFR is present: protein targets should be individualized; KDIGO cautions against high protein intake in CKD at risk of progression
• Avoid exceeding very high intakes for prolonged periods without monitoring kidney function
• Distribute protein intake across 3-4 meals (20-40 g per meal to maximize muscle synthesis)
• Favor mixed sources: fish, legumes, eggs, poultry, dairy. Limit red meat to 1-2 times per week
• If creatinine is borderline high, discuss a possible adjustment with your doctor

What to expect: Balanced protein intake supports muscle mass while avoiding unnecessary kidney workload in people with kidney risk.

4. Control blood sugar

Why it works: Diabetes and hypertension are the major drivers of chronic kidney damage. Excess glucose causes glycation of glomerular proteins, thickening of the basement membrane, and progressively, diabetic kidney disease.

How to do it:

• Keep fasting glucose in the 80-94 mg/dL range (4.4-5.2 mmol/L) — the optimal range for longevity
• Reduce added sugars and refined carbohydrates
• Eat fiber at every meal (slows glucose absorption)
• Exercise after meals: even a 15-20 minute walk reduces glycemic spikes by 20-30%
• Monitor HbA1c (glycated hemoglobin): ideal is < 5.6%

What to expect: Better glucose control lowers diabetic kidney disease risk and helps slow eGFR decline when diabetes or prediabetes is part of the picture.

5. Avoid chronic nephrotoxins

Why it works: Some common substances damage kidneys cumulatively. The damage is often silent — creatinine rises gradually without symptoms — until kidney function is significantly compromised.

Substances to limit:

• NSAIDs (ibuprofen, naproxen, diclofenac): Frequent or chronic use can reduce kidney blood flow, especially with dehydration, CKD, heart failure, older age, or ACE inhibitor/ARB plus diuretic use. Ask your clinician about safer options when you need repeated pain control.
• Excess sodium: > 3,500 mg/day increases intraglomerular pressure
• Excess alcohol: > 2 alcohol units/day for men, > 1 for women
• Smoking: Reduces kidney blood flow and accelerates fibrosis
• Unregulated supplements: Some contain heavy metals or nephrotoxic substances

Caution: This doesn’t mean avoiding medications when necessary. But if you take NSAIDs regularly, discuss less nephrotoxic alternatives with your doctor.

What to expect: Reducing avoidable nephrotoxin exposure helps prevent acute kidney injury and may stabilize creatinine trends over time.

6. Regular (but not extreme) physical exercise

Why it works: Moderate exercise improves kidney circulation, reduces blood pressure, improves insulin sensitivity, and fights inflammation — all factors that protect the kidneys. Additionally, it maintains muscle mass, which is fundamental for aging well.

How to do it:

• Aerobic: 150-300 minutes/week of moderate activity (brisk walking at 3.1-3.7 mph / 5-6 km/h, swimming, cycling)
• Strength: 2-3 sessions/week to preserve muscle mass
• Avoid excesses: Extreme exercise without adequate hydration can cause rhabdomyolysis — a condition where damaged muscle fibers release myoglobin, which can damage kidneys
• Adequate recovery: Chronic overtraining increases inflammation and oxidative stress

What to expect: Regular exercise supports the main kidney-protective levers: blood pressure, insulin sensitivity, body composition, vascular health, and inflammation. Avoid interpreting short-term post-exercise creatinine rises as kidney aging without context.

---

How SuperAge tracks creatinine and calculates your biological age

Monitoring creatinine over time is the best way to understand if your kidneys are aging at the “right” speed or too quickly. The problem? Almost no one keeps track of the evolution of their values over time.

Blood tests become a biological-age estimate

Starting with version 3.2, SuperAge integrates full support for blood tests:

1. Scan or import the PDF of your blood work — the AI automatically recognizes over 40 biomarkers, including creatinine
2. Estimates PhenoAge and shows how creatinine (and the other 8 biomarkers) contribute to your biological-age estimate
3. Identifies critical areas — if creatinine is raising your biological age, you see it clearly in the radar chart
4. Tracks evolution over time — compare your values between blood draws, and monitor whether your estimated eGFR is improving or worsening

The complete picture: blood + Apple Watch

The real power of SuperAge is combining blood test data with Apple Watch data:

• Creatinine tells you how the kidneys are doing at a specific moment
• Resting heart rate and HRV (tracked daily) reflect cardiovascular stress that influences kidney health
• VO2 Max indicates cardiorespiratory fitness — positively correlated with kidney function
• Sleep quality influences nighttime blood pressure, which in turn influences the kidneys

By combining this information, you get a broader and more continuous view of your aging trajectory — not just a static snapshot every 6-12 months.

---

Frequently asked questions

What’s a good creatinine value?

For many adults, values around 0.8-1.0 mg/dL for men and 0.6-0.8 mg/dL for women can be compatible with a favorable kidney-muscle profile. But there is no universal longevity target. Interpret the number with eGFR, UACR, cystatin C when needed, muscle mass, diet, hydration, and medications.

Is high creatinine always a sign of kidney disease?

No. Creatinine can be temporarily elevated after intense exercise, high red meat consumption, creatine supplement use, or dehydration. High muscle mass alone can also push creatinine above the lab reference while eGFR stays normal — a pattern we explain in detail in creatinine high but eGFR normal. If the value is high only once, the doctor will probably advise repeating the test after a few days of adequate hydration and controlled diet. If it remains consistently high, further investigation with eGFR and other tests is necessary.

Should I stop taking creatine as a supplement?

Creatine (supplement) and creatinine (waste product) are different molecules. Creatine supplementation can slightly raise blood creatinine without damaging kidneys in people with normal kidney function. A 2025 evidence review argued that creatine has a strong safety profile across the lifespan and should not be broadly restricted in healthy people. However, if you already have kidney problems, albuminuria, or unexplained abnormal labs, consult your doctor before taking creatine.

Is low creatinine always a good sign?

Not necessarily. In a young person with good muscle mass, low creatinine indicates efficient kidneys — excellent. In an elderly person with reduced muscle mass, an “apparently normal” creatinine could mask kidney failure. This is why it’s essential to always calculate eGFR, which corrects for age and sex.

How long does it take to improve kidney function?

Kidney function responds slowly to lifestyle changes. Improvement or stabilization in kidney markers can sometimes be observed after 3-6 months of well-controlled blood pressure, better glucose control, adequate hydration, and reduction of nephrotoxins. The realistic goal isn’t to “rejuvenate” the kidneys, but to slow avoidable decline and reduce risk.

How often should I check creatinine?

For most healthy people, once a year is sufficient — typically as part of routine blood tests. If you have risk factors (hypertension, diabetes, family history of kidney disease, chronic NSAID use), your doctor might recommend checks every 3-6 months. With SuperAge, you can import each new result and monitor the trend over time.

---

Key takeaways

• Creatinine is much more than a “kidney test”: it’s one of the 9 PhenoAge biomarkers and a kidney-muscle signal linked to mortality risk
• Centenarians tend to have lower creatinine — and this pattern is visible decades before their 100th birthday, but it is not a personal target by itself
• The useful range is contextual: values around 0.8-1.0 mg/dL (men) and 0.6-0.8 mg/dL (women) can be favorable when muscle mass and kidney markers are also healthy
• Always ask for eGFR: creatinine alone can be misleading, especially with advancing age
• The priorities for kidneys are: control blood pressure, control glucose when relevant, check UACR, avoid nephrotoxins, stay reasonably hydrated, and individualize protein
• SuperAge estimates PhenoAge from your blood work and tracks creatinine evolution over time

---

Protect your kidneys, protect your longevity

Kidneys are among the most silent organs in the body: they don’t tell you when they’re suffering. When symptoms appear, the damage is often already advanced. But creatinine — a number you probably already have in your latest blood work — can tell you the story before it’s too late.

Every year your kidneys function well is a year gained in cardiovascular, cognitive, muscular, and immune resilience. It is not that kidneys determine longevity alone; it is that kidney markers are a quiet, powerful window into long-term risk.

Want to know what your creatinine says about your biological-age estimate? Download SuperAge, import your blood work, and track your PhenoAge trend over time.

---

References

1. Murata S, et al. “Blood biomarker profiles and exceptional longevity: comparison of centenarians and non-centenarians in a 35-year follow-up of the Swedish AMORIS cohort.” GeroScience, 2023. DOI: 10.1007/s11357-023-00936-w
2. Levine ME, et al. “An epigenetic biomarker of aging for lifespan and healthspan.” Aging, 2018. DOI: 10.18632/aging.101414
3. Kuo CL, et al. “Genetic associations for two biological age measures point to distinct aging phenotypes.” Aging Cell, 2021. DOI: 10.1111/acel.13376
4. Hommos MS, et al. “Ageing and the glomerular filtration rate: truths and consequences.” Transactions of the American Clinical and Climatological Association, 2017.
5. National Kidney Foundation. “Estimated GFR (eGFR) Test: Kidney Function Levels and Stages.” kidney.org
6. Forbes JM, Cooper ME. “Mechanisms of diabetic complications.” Physiological Reviews, 2013.
7. Kreider RB, et al. “Creatine supplementation is safe, beneficial throughout the lifespan, and should not be restricted.” Frontiers in Nutrition, 2025. DOI: 10.3389/fnut.2025.1578564
8. Vega-Cabello V, et al. “A Systematic Review Comparing the Prognostic Role of eGFR According to CKD-EPI and Older Age Validated Equations in Older Adults.” Kidney Medicine, 2025. DOI: 10.1016/j.xkme.2025.101040
9. Deng Y, et al. “The Predictive Power of the Cystatin C-Creatinine Score in Assessing Frailty.” Journal of Cachexia, Sarcopenia and Muscle, 2025. DOI: 10.1002/jcsm.70040
10. KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney International, 2024.

---

Last updated: 2026-07-08. This article is regularly reviewed for scientific accuracy and does not replace professional medical advice.