Diabetic Kidney Disease: Why a Creatinine Test Isn't Enough, and the Test That Catches It Early

Diabetic kidney disease is damage to the kidneys' microscopic filters caused by years of elevated blood glucose, and it is the quietest of all diabetes complications. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) puts it bluntly: "Most people with diabetic kidney disease do not have symptoms. The only way to know if you have diabetic kidney disease is to get your kidneys checked." The twist is that the test which catches it early is not the blood test most people already get — it is a simple, inexpensive urine test called the urine albumin-to-creatinine ratio (uACR). And it is precisely the test that most people with diabetes never receive.

This article explains why a result reading "kidney function normal" may not be enough, which two numbers you actually need, when to test, and what genuinely slows the disease down according to the best available evidence.

What is diabetic kidney disease, and why does it happen?

Each kidney holds millions of microscopic filters built from extremely fine blood vessels. Their job is to let waste and excess water pass into the urine while keeping the useful things — protein above all — inside the bloodstream. When blood glucose stays high for years, the walls of those tiny vessels are damaged little by little, and they begin to leak what they were built to hold back.

This is the same mechanism that damages the retina and the nerves of the feet. That is why clinicians treat the "microvascular complications" of diabetes as one family: eye, kidney, nerve. Anyone who read our article on diabetic retinopathy will recognise the logic here — a vital organ, fine vessels, cumulative damage, and near-total silence until late.

How common is it? NIDDK states: "About 1 out of 3 adults with diabetes has kidney disease." Mayo Clinic gives the same figure: "In the United States, about 1 in 3 people living with diabetes have diabetic nephropathy." At population level, the Centers for Disease Control and Prevention (CDC) estimates that "about 35.5 million US adults are estimated to have CKD, and most are undiagnosed," and that "diabetes and high blood pressure are the leading causes of kidney failure, accounting for 2 out of 3 new cases."

Why you feel nothing until it is late

The kidney is patient to the point of being misleading. NIDDK is explicit: "Most people in the early stages of CKD do not have symptoms, and many people have no symptoms until their kidney disease is advanced." The reason is functional reserve. When some filtering units fail, the healthy ones take on more of the load, so blood results stay inside the normal range while the damage continues.

The symptoms people actually recognise — the ones Mayo Clinic lists — are: high blood pressure that gets harder to control, swelling of the feet, ankles, hands or around the eyes, foamy urine, shortness of breath, loss of appetite, nausea, itching, tiredness and weakness, and confusion or difficulty thinking. The problem is that these are not early warning signs. They are late signs. Waiting for them before deciding to test means missing the years in which the trajectory could still have been changed.

The practical conclusion is blunt but simple: the absence of symptoms is not evidence of safety — it is exactly why the test exists.

The two numbers that define your kidney health

Kidney health does not reduce to one number. It is two numbers read together, and the one that is routinely skipped is the one that moves first.

Number one: estimated glomerular filtration rate (eGFR)

This is calculated from blood creatinine along with age and sex, and it estimates "how much your kidneys are filtering." It is reported in mL/min/1.73 m². Under the accepted classification, a value below 60 mL/min/1.73 m² is the threshold that triggers a diagnosis. This number tells you about the total remaining capacity of your kidneys.

Number two: urine albumin-to-creatinine ratio (uACR)

Albumin is a relatively large protein that is supposed to stay in the blood. Its appearance in urine means the filter has begun to leak. The reference value is simple. The National Kidney Foundation states: "A normal amount of albumin in your urine is less than 30 mg/g." This number tells you about the integrity of the filter itself, not its capacity.

So why isn't a creatinine test enough on its own?

Here is the sentence worth clipping and keeping. The National Kidney Foundation says it directly: "Anything above 30 mg/g may mean you have kidney disease, even if your estimated glomerular filtration (eGFR) number is above 60."

In other words, a blood test can come back reading as "normal kidney function" while a urine test reveals an active leak. The first measures capacity; the second measures leakage — and leakage precedes the fall in capacity. Relying on creatinine alone means measuring the right thing at the wrong time.

The two numbers are a grid, not a line

The correct way to read the pair is not "which is worse" but where they intersect. The internationally accepted framework (KDIGO) places both on a colour-coded grid: filtration categories on one axis, albuminuria categories on the other, and the resulting cell shaded from green for lowest risk through yellow and orange to red for highest — as the Cleveland Clinic Journal of Medicine summarises it, "a color-coded risk stratification system — green indicates the lowest risk and red the highest."

The definition itself matters because it guards against two opposite errors. The same journal states: "Chronic kidney disease is diagnosed when the eGFR is less than 60 mL/min/1.73 m2, the urinary albumin-to-creatinine ratio is 30 mg/g or higher, or both, on at least 2 measurements taken more than 90 days apart."

What does that mean in practice?

• One high result is not a diagnosis. Fever, infection, hard physical exertion before the test, and a sharp glucose spike can all temporarily raise albumin, which is why the test is repeated. As the National Kidney Foundation puts it: "Two high results for three months or more is a sign of kidney disease."
• And one normal result is not a permanent clearance. Annual screening exists because the picture changes over time.

When should you test, how often, and what exactly should you ask for?

NIDDK's recommendation is clear: get tested for kidney disease every year if you have type 2 diabetes, or if you have had type 1 diabetes for more than five years.

The detail that makes the difference is asking for both tests by name, because many routine "kidney function" panels include creatinine only:

1. Urine albumin-to-creatinine ratio (uACR) — an ordinary urine sample. No fasting, no 24-hour collection.
2. Blood creatinine with a calculated eGFR — and ask that the eGFR figure appear explicitly on the report, not creatinine alone.

Then do one small thing that pays off enormously: keep both numbers, with their dates, in one place. The value of these two numbers is not in a single snapshot but in the trend across years. A clinician who sees two consecutive readings sees something no one can see on a single sheet of paper.

The real gap isn't scientific — it's an appointment that never happened

This is the most frustrating part of the story, and also the most fixable. In a large individual-participant data meta-analysis published in Hypertension, the American Heart Association journal, data were pooled from 1,344,594 adults with diabetes across 31 subcohorts. The finding: only 35.1% had received albuminuria (ACR) screening, with a range of 12.3% to 74.5% between cohorts. Roughly two-thirds of the adults with diabetes in that dataset were never tested at all.

Worse, the researchers calculated the ratio of undetected to detected cases: 1.8 in diabetes — meaning that for every case of albuminuria found, roughly two went unfound. The authors concluded that "regular albuminuria screening should be emphasized to enable early detection of chronic kidney disease and initiation of treatment with cardiovascular and renal benefits."

That explains the CDC's startling figure: "More than 1 in 7 American adults has chronic kidney disease (CKD), and as many as 9 in 10 don't know they have it."

Notice what these numbers do not say. They do not say the science is helpless, or the disease is mysterious, or the test is expensive or painful. They say the test was not ordered. That is a gap a reader can close with one sentence in a clinic.

What actually slows diabetic kidney disease down?

1) Blood glucose control — and the effect lasts decades

The landmark evidence here is the DCCT trial and its EDIC follow-up. NIDDK summarises the results: intensive blood glucose control reduced "diabetic kidney disease by 50 percent"; and in long-term follow-up it reduced "advanced kidney disease by 33 percent, 24 years after the DCCT ended." The message is not about a week or a month — it is about years, which is exactly what makes daily habits, rather than short-term fixes, the real lever.

2) Blood pressure — the silent partner

High blood pressure accelerates kidney damage, and kidney damage raises blood pressure: a loop that closes on itself. NIDDK's guidance: "For most people, the blood pressure goal is less than 140/90 mm Hg," with the caveat that some people need a tighter target as judged by their clinician.

3) ACE inhibitors and ARBs — protection that doesn't wait for hypertension

This drug class has a special role here. NIDDK states that ACE inhibitors and ARBs "may slow kidney disease and delay kidney failure, even in people who don't have high blood pressure." In other words, the presence of albumin in your urine can itself be a reason to discuss these medicines — a purely clinical decision.

4) What has changed in recent years

The part many people are no longer up to date on is that the options for protecting kidneys have genuinely widened, on the strength of large randomised trials — several of which were stopped early because the benefit was so clear:

• DAPA-CKD (published in the New England Journal of Medicine, 2020): 4,304 participants, 67.5% of them with type 2 diabetes, randomised to dapagliflozin 10 mg daily or placebo. The primary composite outcome occurred in 9.2% on the drug versus 14.5% on placebo (hazard ratio 0.61; 95% CI 0.51–0.72; P<0.001). The trial was halted early on the recommendation of its data monitoring board.
• FLOW (New England Journal of Medicine, 2024): 3,533 participants with type 2 diabetes and chronic kidney disease, randomised to semaglutide 1.0 mg weekly or placebo. The composite kidney outcome fell with a hazard ratio of 0.76 (95% CI 0.66–0.88; p = 0.0003), and the annual decline in eGFR was slower by 1.16 mL/min/1.73 m². This trial too was halted early, in October 2023, after interim analysis.

And we say this with complete clarity: nobody starts a medication because of an article. These are drugs with indications, contraindications and side effects, and the decision belongs to a physician alone. The one practical use of knowing they exist is to ask a specific question: "My result shows albumin in my urine — am I a candidate for any of the kidney-protective classes?" Many eligible patients are never asked simply because no one opened the subject.

5) Painkillers — the everyday hazard that gets underestimated

This point deserves particular attention because it happens at home, without a prescription. NIDDK warns: "NSAIDs include commonly used pain relievers and cold medicines that can damage your kidneys and lead to acute kidney injury," and clarifies that "ibuprofen and naproxen are NSAIDs." The practical advice: "Ask your pharmacist or health care provider if the medicines you take are safe to use." Smoking counts too: "Cigarette smoking can make kidney damage worse."

Four common myths worth correcting

• "Drinking lots of water protects my kidneys from diabetes." Adequate hydration is generally good, but it is neither a test nor a treatment for diabetic kidney disease. NIDDK's sentence still stands: the only way to know is to get your kidneys checked.
• "Protein destroys kidneys, so everyone should cut it." This is stated far more absolutely than the evidence warrants. For someone with established chronic kidney disease, NIDDK's position is that the diet is individualised: "There is no single meal plan for everyone with CKD," with a recommendation to work "with a registered dietitian, if possible, to create an eating plan for your individual needs." So protein quantity — up or down — is an individual clinical decision for someone with a diagnosis, not a general rule to self-apply. And for anyone who does not yet know their kidney status, the answer is not guessing or self-restriction — it is testing.
• "Herbs and supplements cleanse the kidneys." Nothing supports that claim, and more importantly, some supplements and over-the-counter medicines may be unsafe with reduced kidney function — which is why asking a pharmacist about everything you take is not a formality.
• "My urine looks normal, so my kidneys are fine." Foamy urine appears in Mayo Clinic's symptom list under the later stages. The absence of foam does not rule out albumin that has been measurable in a lab for years.

The picture in Saudi Arabia

The local figures bring this much closer to daily life in Riyadh and across the Kingdom:

• In a study based on the Saudi National Diabetes Registry, published by Al-Rubeaan and colleagues in PLOS ONE in 2014 and covering 54,670 patients with type 2 diabetes aged 25 and over, the prevalence of diabetic nephropathy was 10.8%, and 1.5% had already reached end-stage renal disease. The gradient matters most: from 3.7% among those aged 25–44 with diabetes duration over five years, up to 21.8% among those aged 65 and over with a duration of 15 years or more.
• In a large population-based study published in BMC Nephrology in 2025, analysing 1,065,755 visits involving 664,684 individuals between 2015 and 2022, the overall prevalence of chronic kidney disease was 4.76% (95% CI 4.72–4.80), most of it in stage 3 (3.5%), higher in males (5.83%) than females (3.88%), and rising sharply with age.
• In a single-centre Riyadh cohort published by Alwakeel and colleagues in Annals of Saudi Medicine in 2011, covering 621 patients with diabetic nephropathy, progression was observed in 73.3%, and 16.5% reached dialysis, with a mean rate of GFR decline of 3.3 mL/min per year. Progression was associated with diabetes duration over ten years, persistent proteinuria, systolic blood pressure above 130 mm Hg — and the presence of retinopathy.

That last point is worth pausing on. Anyone who has been told they have diabetic retinopathy has a direct additional reason to ask about their kidneys at the same visit. The eye and the kidney are injured by the same mechanism, and often in the same window of time.

Who should pay closer attention, and when to see a doctor

Higher likelihood — not certainty — is associated with: long diabetes duration (especially beyond ten years), unstable glucose control, high blood pressure, smoking, high cholesterol, obesity, the presence of retinopathy or diabetic neuropathy, a family history of kidney disease, and older age.

See your doctor without delay if you notice new swelling in the feet or face, clear and persistent foam in the urine, blood pressure that has become hard to control, or an unexplained drop in appetite or energy.

Important note: this article is general education and is not a substitute for consulting your physician or a licensed dietitian. Do not start a medicine, stop one, change a dose, or substantially restrict your diet based on what you read here. If you have diabetes or known kidney disease, every change goes through your medical team.

A practical four-step plan

1. Ask for both numbers by name at your next lab visit: urine albumin-to-creatinine ratio (uACR), and blood creatinine with a calculated eGFR.
2. Record them with their dates in one note on your phone. You are building a trend, not collecting paperwork.
3. If the uACR comes back above 30: don't panic and don't ignore it. Repeat the test on the schedule your doctor sets (a diagnosis requires two measurements more than 90 days apart), and ask explicitly about kidney-protective medicines.
4. Review your medicine cabinet with a pharmacist: painkillers, cold remedies, supplements — which ones are safe specifically for you?

Where does Bakery 8 fit into all this?

No bread treats kidney disease. We say it plainly because honesty matters more than selling: no food replaces an albumin test, and no loaf substitutes for a medicine a doctor prescribes. Claiming otherwise would be a harm, not a service.

But everything above points at the first factor in this story: blood glucose over years. And that is where a repeated daily choice has a genuinely cumulative effect, because bread on a Saudi table is not an occasional item — it is there at breakfast, at dinner, and in between.

At Bakery 8 (مخبز ثمانية) in Riyadh, Saudi Arabia, we make our products from almond flour with no added sugar, for people tracking their blood sugar or following a low-carbohydrate way of eating:

• Samoli bread, cloud bread and toast — a daily alternative to white wheat bread with no added sugar.
• Keto granola — a breakfast with a lighter impact on blood sugar than sweetened cereals.

And if you are tracking blood pressure alongside blood sugar — which, in this story, is likely — read our article on sodium and salt too, because the same table serves both numbers.

Frequently asked questions

Is diabetic kidney disease reversible?

Advanced structural damage generally is not reversed, but finding it early changes its course considerably. The evidence shows that controlling glucose and blood pressure and using kidney-protective medicines under medical supervision meaningfully slow progression, and can lower urine albumin. The key is timing: the earlier you look, the wider the margin for change.

What is the difference between a creatinine test and a urine albumin test?

Blood creatinine is used to estimate filtration rate (eGFR) — "how much your kidneys filter." Urine albumin reveals whether the filter is leaking. Leakage usually precedes a fall in filtration, so eGFR can be normal while uACR is high. That is why both tests are recommended together, not one of them.

How often should I get my kidneys checked if I have diabetes?

NIDDK recommends annual testing for people with type 2 diabetes, and for those who have had type 1 diabetes for more than five years. Your doctor may test sooner if results are abnormal or if blood pressure or glucose is not controlled. Keeping that yearly appointment is the simplest preventive step available.

Does a high-protein diet harm the kidneys?

For someone with established chronic kidney disease, protein intake is an individual clinical decision; NIDDK states that "there is no single meal plan for everyone with CKD" and recommends working with a registered dietitian. For anyone who does not know their kidney status, the practical answer is neither self-restriction nor guesswork — it is running the uACR and eGFR tests and building the decision on a real number.

Does foamy urine always mean kidney disease?

Not necessarily; foam can come from the speed of urine flow or other causes. But persistent foam is listed by Mayo Clinic among the symptoms of later-stage diabetic kidney disease, which makes it worth a medical review and an albumin test rather than watchful waiting.

Can my eGFR be normal and still have kidney disease?

Yes — and this is the central point of the article. The National Kidney Foundation states that an albumin result above 30 mg/g may mean kidney disease "even if your estimated glomerular filtration (eGFR) number is above 60." That is why being told your "kidney function is normal" is not enough if nobody asked about the urine test.

Conclusion

Diabetic kidney disease does not shout, and it does not wait for you to notice. It starts as a small leak you cannot feel and a routine blood test cannot see, and it runs for years before it says anything at all. The good news is that catching it needs no rare technology and no great expense — it needs one sentence in a clinic: "I'd like a urine albumin test along with the creatinine."

Between one appointment and the next, daily habits are what move both numbers slowly in the right direction. If you are looking for breads and desserts with no added sugar and low carbohydrate that fit the way you track your blood sugar, browse the Bakery 8 range — healthy and delicious, made for people who read their own numbers.

References

• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Diabetic Kidney Disease. NIH.
• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). What Is Chronic Kidney Disease? NIH.
• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Managing Chronic Kidney Disease. NIH.
• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Eating Right for Chronic Kidney Disease. NIH.
• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Blood Glucose Control Studies for Type 1 Diabetes: DCCT and EDIC. NIH.
• Centers for Disease Control and Prevention (CDC). Chronic Kidney Disease Basics. 2025.
• Mayo Clinic. Diabetic Nephropathy (Kidney Disease) — Symptoms and Causes.
• National Kidney Foundation. Urine Albumin-Creatinine Ratio (uACR).
• Cleveland Clinic Journal of Medicine. Managing Chronic Kidney Disease According to KDIGO Risk Categories: A Primer for Primary Care. 2026;93(6):353.
• Chronic Kidney Disease Prognosis Consortium. Albuminuria Testing in Hypertension and Diabetes: An Individual-Participant Data Meta-Analysis in a Global Consortium. Hypertension (American Heart Association), 2021.
• Heerspink HJL, et al. Dapagliflozin in Patients with Chronic Kidney Disease (DAPA-CKD). New England Journal of Medicine, 2020.
• Perkovic V, et al. Effects of Semaglutide on Chronic Kidney Disease in Patients with Type 2 Diabetes (FLOW). New England Journal of Medicine, 2024.
• Al-Rubeaan K, et al. Diabetic Nephropathy and Its Risk Factors in a Society with a Type 2 Diabetes Epidemic: A Saudi National Diabetes Registry-Based Study. PLOS ONE, 2014.
• Alwakeel JS, et al. Factors Affecting the Progression of Diabetic Nephropathy and Its Complications: A Single-Center Experience in Saudi Arabia. Annals of Saudi Medicine, 2011;31(3):236–242.
• Alshahrani S, et al. Prevalence of Chronic Kidney Disease in Saudi Arabia: An Epidemiological Population-Based Study. BMC Nephrology, 2025.

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