GLP-1 Medications and Kidney Health

Most of the attention on GLP-1 medications goes to weight, and lately to the heart. Another organ is getting interest too: the kidneys. A large trial called FLOW looked at what a once-weekly GLP-1 medication does for people who already have kidney disease. This is general education, not medical advice, and the study population is specific, so please read on carefully.

Who was studied

The FLOW trial, published in the New England Journal of Medicine in 2024 by Perkovic and colleagues, enrolled 3,533 people with type 2 diabetes and chronic kidney disease across 28 countries. They were randomly assigned to once-weekly semaglutide or a placebo, in addition to their usual care. They were not people taking the medication for weight loss, which is an important difference from the weight-management trials we cover elsewhere.

The main results

• The main outcome combined several serious events: kidney failure, a sustained drop in kidney function of at least 50 percent, and death from kidney or heart causes.
• People taking semaglutide had a 24 percent lower risk of that combined outcome than people taking the placebo.
• Median follow-up was about 3.4 years. The independent monitoring committee recommended stopping the trial early because the benefit was clear.
• A later analysis reported that kidney and survival benefits appeared whatever the stage of kidney disease, including more advanced disease.

Why the kidneys might benefit

Researchers think several things may play a part: improved blood sugar, lower blood pressure, less body weight and less inflammation. None of these is fully settled, and the trial was not designed to prove how the benefit works. Our look at the SELECT trial describes a similar story for the heart.

What this does and does not mean

• It applies to a specific group. The results come from adults with type 2 diabetes and kidney disease. They do not show the same effect in people without these conditions.
• It does not replace regular kidney care. People with kidney disease still need monitoring, blood pressure and blood sugar management, and their own clinician’s advice.
• Kidneys and hydration go together. The prescribing information for these medications warns about kidney injury in people who become dehydrated, which is one reason fluids matter. Our guide to eating well on a GLP-1 medication covers this.
• Eligibility is a medical decision. Our guide on who qualifies for a GLP-1 medication explains the labeled criteria in general terms.

The wider picture

FLOW adds to a growing list of effects that go beyond the scale, which researchers are still sorting out. For anyone with diabetes and kidney concerns, it is a reason to ask their care team whether this class of medication has a place in their plan. For everyone else, it is a good reminder that long-term health is bigger than a single number.

Sources

• Perkovic V, Tuttle KR, Rossing P, et al. Effects of semaglutide on chronic kidney disease in patients with type 2 diabetes (the FLOW trial). New England Journal of Medicine, 2024 (figures here come from trial summaries and the registry, not the full paper; check the paper for exact numbers).
• FLOW (NN9535-4321) semaglutide renal outcomes trial, Health Research Authority research summary.