SGLT2 inhibitors protect kidneys most when urine shows protein, study finds

If you have type 2 diabetes, a simple urine test can tell you a lot about how much your kidneys stand to gain from newer medicines. A large new study found that SGLT2 inhibitors, and the related GLP-1 drugs, lowered the chance of kidney decline in people who had protein in their urine. In people without protein, the study did not see a clear kidney benefit over the years it followed them.

That is useful to know, and it is not a reason to worry. The test is quick, and it gives you something concrete to ask about.

How the study worked

Researchers combined health records and insurance data from 10 health systems and two national insurance plans, covering a large group of adults with type 2 diabetes. Everyone was taking metformin and then started a second medicine between 2014 and 2022, either an SGLT2 inhibitor or GLP-1 drug, or an older option such as a DPP-4 inhibitor. The typical person was 60 years old, 48% were women, and people were followed for a typical (median) 32 months. The work appeared Sept. 16, 2026, in The BMJ, and because it looked back at records rather than assigning treatments at random, lumped the two drug classes together, and followed people for a few years, it cannot say what happens over a decade or more.

What they found

Most people in the study (81.76%) had no protein in their urine. For them, the five-year chance of kidney decline was about the same whichever medicine they took: 2.4% with an SGLT2 inhibitor or GLP-1 drug, and 2.1% with a DPP-4 inhibitor. The study saw no clear kidney advantage in this group.

For people with protein in their urine, the picture changed. Their five-year chance of kidney decline was 3.2% with an SGLT2 inhibitor or GLP-1 drug, compared with 5.4% with a DPP-4 inhibitor. That is a clearly lower chance. In the study’s exact figure, the risk with the newer drugs was 0.60 times the risk with the DPP-4 inhibitor.

“Kidney decline” here meant one of two things: the blood creatinine level doubling, or kidney filtering falling to a very low level.

What does protein in the urine mean?

The medical word is albuminuria. Albumin is a protein that healthy kidneys keep in the blood. When the kidney’s tiny filters are under strain, a little leaks into the urine. The study counted albuminuria as 30 mg or more of albumin for each gram of creatinine in the urine.

This is often an early sign, and it can show up before you feel anything. That is why a urine test is useful. A blood test alone can look fine while the urine already shows a change.

What this does and does not mean

This study looked only at kidney outcomes. SGLT2 inhibitors and GLP-1 drugs also help with blood sugar, the heart and weight, and none of that is touched by these results. If you are already taking one of these medicines, nothing here says to stop. The results simply suggest the kidney benefit is clearest for people whose urine already shows protein.

The researchers also point out that they saw little kidney benefit in people without protein over the follow-up period. Longer studies may show more. For now, the urine test helps your doctor match the medicine to your situation.

What you can do today

Look at your last set of lab results, in your patient portal or on paper, and see whether it includes a urine albumin test. This is different from the blood creatinine test. If you cannot find one, ask your care team to add it at your next visit. Then you will know your own number, and your doctor can weigh it alongside your heart, weight and blood sugar goals.