Declining eGFR value? 6 tips to support your kidney function also with creatine supplements.

A declining eGFR does not immediately mean kidney damage, but does require attention and possibly repeat measurements. With the right lifestyle, blood tests and counseling, you can often stabilize or improve your kidney function.

You get your blood tested regularly and have noticed your eGFR level slowly declining. Does this mean your kidneys are deteriorating? Not necessarily. An eGFR is an estimate based on the amount of creatinine in your blood. That result can also be influenced by factors such as your muscle mass, creatine use, or a temporary illness.

Still, a declining eGFR is something to take seriously. Especially if the decline is noticeable or recurs in a subsequent test, you’ll want to know what’s causing it. With blood tests, an ACR urine test, and attention to your lifestyle, you can get a better picture of your kidney health.

What does your eGFR level mean?

eGFR stands for estimated glomerular filtration rate. This value estimates how well your kidneys filter your blood. The lab usually calculates the eGFR using the creatinine level in your blood and factors such as your age.

An eGFR below 60 ml/min/1.73 m² may indicate reduced kidney function. But a single result doesn’t tell the whole story. Even with a higher eGFR, a noticeable decline compared to previous measurements may be a reason to investigate further. Your doctor will therefore evaluate the trend in your test results and check for albumin in your urine.

My eGFR is dropping. What should I do?

First, compare your results with previous measurements. Is this the first time your eGFR has been measured, or is the value significantly lower than before? If so, contact your primary care physician. Sometimes it’s wise to have your kidney function rechecked soon, to ensure an acute problem isn’t overlooked. If the deviation is minor, a follow-up check at a later date may be appropriate. The recommended timeframe depends on your specific situation.

When filling out that assessment, please also mention whether you take creatine, engage in intense exercise, or take any medications. This will help ensure the results are interpreted correctly.

6 Tips to Support Your Kidney Function

1. Check your blood pressure

High blood pressure can damage the kidney filters. Conversely, reduced kidney function can also contribute to high blood pressure. Therefore, have your blood pressure checked, especially if your eGFR is dropping. Your primary care physician can discuss with you what blood pressure level is appropriate for you and whether lifestyle changes or treatment are necessary.

2. Watch your salt intake and discuss your protein intake

Cutting back on salt is a practical step to support your blood pressure and kidney health. Cook with fresh ingredients more often, and taste your food before adding extra salt.

Do you exercise a lot and eat a high-protein diet? Be sure to mention this when you discuss your results. Don’t start a strict low-protein diet on your own. Whether adjusting your protein intake is advisable depends on your kidney function, your diet, and any other medical conditions you may have. A dietitian with expertise in kidney disease can help you with this.

3. Take a critical look at your medications and supplements

Anti-inflammatory pain relievers such as ibuprofen and naproxen require extra caution if your kidney function is impaired. Supplements and herbal remedies are also not automatically suitable for everyone.

Make a list of everything you’re taking, including creatine, and discuss it with your doctor or pharmacist. Do not stop taking prescribed medications on your own. Do you have questions about combining medications and supplements? If so, you can also request an e-consultation with a pharmacist.

4. Prevent dehydration, but don’t drink too much

You can lose a lot of fluid if you have a fever, diarrhea, vomiting, or engage in intense exercise. Tell your doctor if you were sick or possibly dehydrated around the time of the blood draw. This can be important when evaluating your eGFR.

Drinking extra water to “boost” a low eGFR is pointless. Drink according to your individual circumstances and follow any fluid intake recommendations from your healthcare provider.

5. Have your urine tested as well

A blood test measuring creatinine and eGFR provides insight into your kidneys’ estimated filtration function. However, kidney damage can sometimes already be detected in the urine even before the eGFR has decreased.

The ACR urine test measures the ratio of albumin to creatinine in your urine. This test checks whether albumin is being lost through your kidney filters. The combination of eGFR and ACR provides a more complete picture than a blood creatinine measurement alone.

Depending on your results, your doctor may recommend additional blood tests, such as for potassium or anemia. Not everyone with a declining eGFR needs the same comprehensive list of blood tests.

6. Find out what’s causing the decline

A declining eGFR is a warning sign, not a diagnosis. High blood pressure, diabetes, medications, and a temporary illness can all play a role. Sometimes, testing for kidney disease is necessary. By identifying the cause, it becomes clear which checkups and measures are appropriate for you.

Creatine Use and a Low eGFR: What’s the Connection?

Do you take creatine supplements for strength training or sports? If so, it’s important to mention this when you get your blood test.

Creatine and creatinine are different substances. Some of the creatine in your body is converted into creatinine. As a result, your creatinine level may be higher and the eGFR calculated from it may appear lower, without this automatically meaning that your kidneys are functioning less effectively. A high amount of muscle mass can also make it more difficult to interpret creatinine levels.

An additional cystatin C test can help in this case. Cystatin C is less dependent on your muscle mass than creatinine. It is not a definitive result on its own: this value must also be evaluated in conjunction with your overall health and other test results. So don’t assume, without further investigation, that a declining eGFR is caused solely by creatine.

Which kidney function tests are right for your situation?

Do you have a lower eGFR and aren’t taking creatine? If so, the trends in your creatinine and eGFR levels, as well as your urinary ACR, are often good first topics to discuss with your primary care physician.

Do you take creatine or have a lot of muscle mass? If so, cystatin C can provide additional information. The ACR urine test answers a different question: whether albumin is being lost through the kidneys. That’s precisely why these tests can complement each other.

A comprehensive health check, such as InsideTracker Ultimate, can provide insight into a wider range of blood values. Be sure to check exactly which kidney values are included: a general check does not automatically replace an ACR urine test.

Frequently Asked Questions About a Declining eGFR

Can my eGFR level go back up?

That’s possible. Sometimes a temporary factor contributed to the lower result. Whether your kidney function actually recovers or remains stable depends on the cause. Therefore, compare multiple test results and discuss a persistent decline with your primary care physician.

Does an eGFR below 60 mean I have chronic kidney damage?

Don’t base your assessment on a single measurement. You need to determine whether the abnormality persists and whether there are other signs of kidney damage, such as an elevated ACR in the urine.

Is cystatin C more reliable if I take creatine?

In this situation, cystatin C can provide useful additional information, because creatine use can affect the creatinine-based eGFR. Which result provides the best picture depends on your personal situation. Always discuss abnormal values with a doctor.

Is your eGFR dropping? Then look beyond just one number. Bring your previous results, list your medications and supplements, and discuss whether a repeat test, an ACR urine test, or a cystatin C test would be beneficial.

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