If you have diabetes, your kidneys deserve the same attention as your A1C. Kidney damage from diabetes usually causes no symptoms until it is advanced, yet it can be found early with two simple tests, and treatment over the last several years has improved more than many people realize.

How diabetes affects the kidneys

NIDDK calls diabetes the leading cause of kidney disease. High blood glucose can injure the small blood vessels in the kidneys over time, and high blood pressure, which many people with diabetes also have, adds further damage.

The numbers are significant. Using national data from 2021 to 2023, the CDC estimates that about 38 percent of adults with diabetes have chronic kidney disease. NIDDK also offers a reassuring point: most people with diabetes and kidney disease do not go on to kidney failure.

The two tests to ask for every year

NIDDK recommends kidney testing every year for people with type 2 diabetes, and for those who have had type 1 diabetes for more than five years. Testing means both:

  • A urine albumin test (UACR), which can show leaking albumin while filtering is still normal
  • A blood test for eGFR, which estimates how well the kidneys filter

Both matter. Our guides to the UACR test and to CKD stages explain how the results combine. A common gap in diabetes care is a yearly blood panel without the urine test, so it is worth asking whether yours included one.

The basics still do most of the work

NIDDK and the CDC agree on the foundations: keep blood glucose in your target range, control blood pressure, manage cholesterol, limit sodium, eat more fruits and vegetables, stay active and take medicines as directed. NIDDK notes that an A1C below 7 percent is a common goal, though targets are set individually.

For blood pressure, NIDDK and the CDC cite a goal below 140/90 for most people with diabetes, or the target your doctor sets. Kidney and heart guidelines often aim lower: the 2024 KDIGO guideline suggests a systolic target under 120 for adults with CKD when it is tolerated. The right number for you depends on your age, other conditions and how you feel on treatment.

Diet changes once kidney disease is present. KDIGO suggests sodium under 2 grams a day for people with CKD and protein around 0.8 grams per kilogram of body weight for those at stage 3 or beyond, with help from a renal dietitian. Our article on prediabetes and A1C covers glucose numbers in more depth.

Medicines that protect the kidneys

This is where care has changed most. Several drug classes now have large trials showing they slow kidney damage in people with type 2 diabetes, beyond what they do for blood sugar.

  • ACE inhibitors and ARBs. NIDDK notes these blood pressure medicines (names ending in -pril or -sartan) slow kidney damage in people with diabetes. KDIGO recommends them for people with diabetes and moderately or severely increased albuminuria. They are not safe in pregnancy.
  • SGLT2 inhibitors. In the CREDENCE trial, canagliflozin lowered the risk of a combined kidney and heart outcome by 30 percent in people with type 2 diabetes and kidney disease. KDIGO recommends an SGLT2 inhibitor for people with type 2 diabetes, CKD and an eGFR of at least 20.
  • Finerenone. In the FIDELIO-DKD trial, this non-steroidal medicine reduced kidney disease progression in people with type 2 diabetes who were already on an ACE inhibitor or ARB. Potassium needs monitoring.
  • GLP-1 receptor agonists. In the FLOW trial, weekly semaglutide reduced major kidney events by 24 percent in people with type 2 diabetes and CKD. KDIGO recommends a long-acting GLP-1 medicine with proven heart benefit when glucose targets are not met on metformin and an SGLT2 inhibitor, or when those cannot be used.

These medicines are often used together, and each needs labs to monitor kidney function and potassium. Doses of some diabetes medicines, metformin among them, depend on eGFR. Our article on GLP-1 medicines covers that class more broadly.

When to call a doctor

Call your doctor if your UACR is 30 mg/g or higher, if your eGFR has dropped since the last test, or if you notice new swelling, foamy urine or much less urine. Seek care quickly for vomiting that prevents you from keeping fluids down while you take diabetes medicines, since dehydration is hard on the kidneys. For chest pain, severe shortness of breath or confusion, call 911.

Diabetes and kidney disease overlap constantly, and Dr. Yana Shtern is board-certified in both Internal Medicine and Nephrology, so one doctor can follow your A1C, blood pressure and kidney numbers together. You can read more on our chronic care and kidney care pages. A complimentary meet and greet is a simple way to see whether the practice is a good fit.

This article is general information, not advice for your situation. Members can call the office with questions about their own care.