Diabetes kidney damage: the two tests your A1c misses
Updated: 4 hours ago
The short answer
A normal-looking A1c cannot tell you whether your kidneys are healthy. Diabetes can raise pressure inside kidney filters, and kidney disease can progress even without obvious protein in the urine. Ask about both eGFR, the blood-based filtering estimate, and UACR, the urine albumin-to-creatinine ratio. Blood-sugar control matters, but the strongest kidney-protection plan also addresses pressure, albumin leakage and kidney-protective medicines rather than relying on A1c alone.
What we cover
Why diabetes can increase pressure inside the filters while a filtering estimate still looks reassuring. Review
How diabetic kidney disease has changed: less albumin leakage in some groups, but more reduced filtration. Primary source
What intensive glucose control did across four trials involving 27,049 people, and what counted as a kidney event. Primary source
Why ACCORD stopped its intensive-glucose arm early after more deaths, and why pushing A1c down is not the whole kidney plan. Primary source
Why anemia and red-cell turnover can make A1c less reliable in advanced kidney disease, and how eGFR and UACR fill different gaps. Guideline
SGLT2 inhibitors: across 90,409 participants, kidney-disease progression fell by 37 percent, with benefit in people without diabetes too. Primary source
The early eGFR dip after an SGLT2 inhibitor, and where finerenone fits in a broader kidney-protection discussion. Primary source
Timestamps
0:00 Your sugar test cannot see your kidneys
1:26 Part one: why your sugar number misses your kidneys
2:49 Part two: the damage looks different now
4:27 Part three: how much does lowering your sugar help
5:30 The trial that pushed sugar too low
6:54 Why your A1c may not be accurate
7:57 Part four: the two numbers to ask for
10:25 Part five: protection that does not go through your sugar
12:58 What this changes
References
Tonneijck L, et al. J Am Soc Nephrol. 2017;28(4):1023-1039. https://pubmed.ncbi.nlm.nih.gov/28143897/
Explains diabetic hyperfiltration and the pressure mechanisms that can precede loss of filtration. Evidence type: narrative review.
Afkarian M, et al. JAMA. 2016;316(6):602-610. https://pubmed.ncbi.nlm.nih.gov/27532915/
US population data showed changing patterns of albuminuria and reduced eGFR among adults with diabetes. Evidence type: observational population study.
Zoungas S, et al. Lancet Diabetes Endocrinol. 2017;5(6):431-437. https://pubmed.ncbi.nlm.nih.gov/28365411/
Pooled four randomized trials to examine the kidney and other microvascular effects of intensive glucose control. Evidence type: individual-participant meta-analysis.
ACCORD Study Group. N Engl J Med. 2008;358(24):2545-2559. https://pubmed.ncbi.nlm.nih.gov/18539917/
The intensive-glucose arm was stopped early because mortality was higher. Evidence type: randomized trial.
American Diabetes Association. Chronic Kidney Disease and Risk Management: Standards of Care in Diabetes 2026. Diabetes Care. 2026;49(Suppl 1):S246-S260. https://pubmed.ncbi.nlm.nih.gov/41358881/
Recommends assessment with both eGFR and urine albumin and describes diabetes-specific kidney management. Evidence type: clinical guideline.
de Boer IH, et al. Diabetes Care. 2022;45(12):3075-3090. https://pubmed.ncbi.nlm.nih.gov/36189689/
Combines diabetes and kidney guidance for assessment, blood pressure, glucose and kidney-protective treatment. Evidence type: consensus report.
Nuffield Department of Population Health Renal Studies Group and the SGLT2 Cardio-Renal Trialists' Consortium. Lancet. 2022;400(10365):1788-1801. https://pubmed.ncbi.nlm.nih.gov/36351458/
Across 90,409 participants, SGLT2 inhibitors reduced kidney-disease progression by 37 percent, including without diabetes. Evidence type: meta-analysis of randomized trials.
Kraus BJ, et al. Kidney Int. 2021;99(3):750-762. https://pubmed.ncbi.nlm.nih.gov/33181154/
Examines the early eGFR dip during SGLT2-inhibitor treatment and its relation to subsequent outcomes. Evidence type: secondary analysis of a randomized trial.
Neuen BL, et al. Lancet. 2026;407(10546):2375-2386. https://pubmed.ncbi.nlm.nih.gov/42248158/
Pooled finerenone evidence across 14,574 participants to assess kidney and cardiovascular outcomes. Evidence type: pooled analysis of randomized trials.
Heerspink HJL, et al. N Engl J Med. 2026;395(6):533-545. https://pubmed.ncbi.nlm.nih.gov/42246672/
Tests finerenone in people with chronic kidney disease without diabetes. Evidence type: randomized trial.
One study explained in plain language every week, with sources attached, plus the free kidney health guide: https://guides.selfprinciple.org/kidney
This content is for educational purposes only and is not medical advice. Always consult your healthcare provider for individual care. The views expressed are Dr. Sean Hashmi's own and do not represent his employer.
Never start, stop, or change the dose of any prescription medication without consulting your physician.
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