When a health check shows a decline in eGFR, many people’s first reaction is: “Is my kidney function getting worse?”
eGFR, or estimated glomerular filtration rate, is an important clinical indicator used to assess kidney function. However, a drop in eGFR from 70 to 60, or even a short-term decline of 10% to 20%, does not necessarily mean that chronic kidney disease is worsening.
To determine whether kidney function is truly deteriorating, it is not enough to compare only two test results. The overall magnitude of decline, the rate of decline, whether the CKD stage has changed, and whether there are reversible factors such as dehydration, infection, or medication effects should all be considered.
What Is eGFR? What Is Considered a Normal eGFR?
eGFR stands for Estimated Glomerular Filtration Rate. It is generally calculated using serum creatinine, age, and validated formulas to estimate how well the kidneys are filtering blood.
In general, the lower the eGFR, the lower the kidney filtration function. Chronic kidney disease can be categorized by eGFR as follows:
G1: eGFR 90 or above
G2: eGFR 60 to 89
G3a: eGFR 45 to 59
G3b: eGFR 30 to 44
G4: eGFR 15 to 29
G5: eGFR below 15
However, a single low eGFR result is not enough to diagnose chronic kidney disease. In addition to the eGFR value itself, clinicians also assess whether the abnormality has persisted for at least three months and whether there is proteinuria or other evidence of kidney damage.
How Much of a Decline in eGFR Is Considered Clinically Significant?
To determine whether a decline in eGFR is clinically meaningful, three factors are usually considered: the magnitude of decline, the rate of decline, and whether the patient has progressed to a more advanced CKD stage.
Previous KDIGO definitions considered a decline in eGFR of 25% or more together with progression to a more advanced CKD stage as an important sign of disease progression. For example, if a patient’s eGFR decreases from 55, which is classified as G3a, to 40, which falls into G3b, this is generally more concerning than a simple fluctuation of 5% to 10%.
However, current clinical practice places greater emphasis on long-term trends rather than relying on a single cutoff value.
The KDIGO 2024 guideline also notes that eGFR is subject to biological and analytical variability. Therefore, if a follow-up eGFR changes by more than approximately 20% compared with the previous result, the change exceeds the expected range of normal variability and warrants further evaluation.
In other words, a single decline in eGFR should not immediately be interpreted as “sudden kidney failure,” but it should not be ignored either. Repeat testing is often necessary to confirm whether the change is persistent.
How Much eGFR Decline Per Year Is Too Fast?
Kidney function may gradually decline with age, so the key issue is not only whether eGFR is decreasing, but also how quickly it is decreasing.
In earlier KDIGO definitions, a sustained decline in eGFR of more than 5 mL/min/1.73m² per year was considered an important marker of rapid progression.
Some studies have used an annual decline of more than 3 to 4 mL/min/1.73m² as a threshold suggesting faster-than-expected kidney function loss.
A 10-year follow-up study in Taiwan defined rapid progression as an annual eGFR decline of more than 3 mL/min/1.73m² and found that patients with more advanced stages of chronic kidney disease had a higher risk of rapid progression.
Therefore, rather than focusing on a single laboratory report, comparing creatinine and eGFR results over several years usually provides a more accurate picture of the true kidney function trend.
Does a Sudden Drop in eGFR Always Mean Chronic Kidney Disease Is Worsening?
Not necessarily.
When eGFR suddenly decreases, the first step in clinical practice is usually not to assume that chronic kidney disease has progressed, but to determine whether there is a temporary or reversible cause.
Common causes include dehydration, fever, infection, diarrhea, vomiting, urinary tract obstruction, and certain medications that may affect kidney function or serum creatinine levels.
For example, nonsteroidal anti-inflammatory drugs (NSAIDs) may affect blood flow to the kidneys in certain situations. Contrast agents and some other medications may also require careful evaluation depending on the patient’s baseline kidney function and overall condition.
Therefore, if eGFR suddenly falls over a short period of time, it is important to review recent illnesses, hydration and nutritional status, and all medications being used rather than stopping medications on your own or taking so-called “kidney-boosting” products without professional guidance.
If eGFR Drops After Starting Kidney-Protective Medication, Should the Medication Be Stopped?
Not necessarily.
ACE inhibitors, ARBs, and SGLT2 inhibitors are commonly used kidney-protective medications in selected patients with chronic kidney disease. After treatment begins, changes in intraglomerular hemodynamics may cause an initial decline in eGFR.
This does not necessarily mean that the medication is “damaging the kidneys.”
In particular, SGLT2 inhibitors may cause an initial dip in eGFR after treatment starts, followed by stabilization. Clinicians generally consider the degree of decline, blood pressure, potassium levels, hydration status, and other medical conditions when deciding whether treatment should be adjusted.
For this reason, patients should not stop ACE inhibitors, ARBs, or SGLT2 inhibitors on their own simply because eGFR has decreased.
What Should You Do if eGFR Keeps Declining?
If repeat testing confirms that eGFR continues to decline, the next step is to identify the underlying cause of worsening kidney function.
In addition to repeating serum creatinine and eGFR testing, clinicians may also evaluate the urine albumin-to-creatinine ratio (ACR), proteinuria, and urinalysis findings.
If the patient also has significant hematuria, proteinuria, difficult-to-control hypertension, persistent electrolyte abnormalities, or unexplained rapid kidney function decline, more intensive evaluation may be necessary.
Treatment should focus on individual risk factors, including control of blood pressure, blood glucose, and proteinuria, as well as the use of kidney-protective therapies such as RAS blockade and SGLT2 inhibitors when clinically appropriate.
At What eGFR Level Should You See a Nephrologist?
The decision to refer a patient to a nephrologist should not be based on a single number alone.
In general, an eGFR below 30 mL/min/1.73m², significant albuminuria or proteinuria, unexplained hematuria, persistent electrolyte abnormalities, resistant hypertension, or rapid deterioration in kidney function are all situations in which nephrology evaluation should be considered.
Recent KDIGO guidelines also emphasize the use of kidney failure risk prediction tools that combine information such as eGFR and urine albumin levels to estimate future kidney failure risk rather than relying solely on CKD stage.
How Often Should Kidney Function Be Checked?
Patients with stable chronic kidney disease generally require regular monitoring of eGFR and urine albumin, but the exact frequency depends on CKD stage, degree of proteinuria, and risk of disease progression.
If eGFR has recently declined, medications have just been adjusted, or acute kidney injury is suspected, follow-up testing may need to be performed within a few weeks.
If the patient’s condition is stable, follow-up intervals may range from several months to once a year depending on the physician’s assessment.
The key point is that there is no single fixed interval that is appropriate for everyone. Monitoring should be frequent enough to identify the true trend in kidney function.
FAQ: Common Questions About Declining eGFR
Q1: Is It Serious if eGFR Drops From 70 to 60?
It cannot be determined from these two values alone. The testing interval, changes in creatinine, possible dehydration or infection, and whether the decline persists on follow-up all need to be considered. If the change is only a temporary fluctuation, eGFR may improve on repeat testing.
Q2: Does a 20% Drop in eGFR Mean the Kidneys Are 20% Damaged?
No. eGFR is an estimated value and cannot be interpreted as the percentage of kidney tissue that is damaged. However, a change of more than 20% during follow-up is significant enough to warrant further evaluation.
Q3: Can eGFR Improve After It Has Decreased?
Yes, in some cases. If the decline is related to reversible causes such as dehydration, infection, urinary tract obstruction, or medication effects, eGFR may improve once the underlying issue is corrected. If the decline is caused by established chronic structural kidney damage, the main goal of treatment is usually to slow further deterioration.
Q4: Does an eGFR Below 60 Automatically Mean Chronic Kidney Disease?
No. Chronic kidney disease generally requires abnormalities in kidney structure or function to persist for at least three months, or there must be other evidence of kidney damage. A single eGFR result below 60 is not enough to make the diagnosis.
Q5: Can I Take Supplements or Chinese Herbal Medicine on My Own if My Kidney Function Is Declining?
Self-medication is not recommended. Even though some herbs is beneficial for CKD, but some medications, herbs, and dietary supplements may place additional stress on the kidneys or interact with prescription drugs. If eGFR is persistently declining, the underlying cause should be identified first, and treatment should be individualized by a qualified healthcare professional based on kidney function and the patient’s overall condition.
References
- Kidney Disease: Improving Global Outcomes (KDIGO). KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney International. 2024.
- Scandrett K, Sitch AJ, Barratt J, et al. Accuracy of glomerular filtration rate estimation based on creatinine and cystatin C for monitoring moderate chronic kidney disease in adults: prospective, longitudinal cohort study. BMJ. 2026.
- Tsai CW, Ting IW, Yeh HC, Kuo CC. Longitudinal Change in Estimated GFR Among CKD Patients: A 10-Year Follow-Up Study of an Integrated Kidney Disease Care Program in Taiwan. PLoS One. 2017.
- Chen TK, Knicely DH, Grams ME. Chronic Kidney Disease Diagnosis and Management: A Review. JAMA. 2019.
- Levey AS, Grams ME, Inker LA. Uses of GFR and Albuminuria Level in Acute and Chronic Kidney Disease. New England Journal of Medicine. 2022.