In clinical research, there's a special kind of good news: when a trial is stopped early because the treatment is working so well that it would be unethical to keep giving some participants a placebo.
That's exactly what happened with FLOW—the first dedicated trial of a GLP-1 medication for kidney disease.
What Was the FLOW Trial?
FLOW enrolled people with type 2 diabetes who also had chronic kidney disease (CKD)—a population at very high risk for progressing to dialysis or dying from cardiovascular causes. The question: could semaglutide slow kidney decline?
The answer came faster than expected.
The Results: Across-the-Board Protection
The primary endpoint—a composite of kidney failure, 50% decline in kidney function, or kidney/cardiovascular death—was reduced by 24% in the semaglutide group.
But it wasn't just kidneys. Participants on semaglutide also had:
- 20% lower risk of dying from any cause
- 18% lower risk of cardiovascular death
- Significant reductions in major cardiovascular events
- Slower decline in eGFR (the measure of kidney function)
How Does Semaglutide Protect Kidneys?
The mechanisms appear to be multiple:
- Improved blood sugar control: High glucose damages kidney blood vessels over time
- Weight loss: Reduces the metabolic burden on kidneys
- Blood pressure reduction: GLP-1s promote sodium excretion, lowering BP
- Direct anti-inflammatory effects: May reduce kidney inflammation independent of glucose
- Cardiovascular protection: Since heart and kidney health are linked, protecting one helps the other
Importantly, the kidney benefits appeared even in participants whose blood sugar was already well-controlled—suggesting the drug does more than just lower glucose.
FDA Approval: A New Indication
Based on FLOW, the FDA expanded semaglutide's approved uses. Ozempic is now indicated to reduce the risk of major kidney disease events in adults with type 2 diabetes and chronic kidney disease.
This makes semaglutide one of the few medications proven to both:
- Protect the heart (SELECT trial)
- Protect the kidneys (FLOW trial)
Who Might Benefit?
If you have type 2 diabetes and any stage of chronic kidney disease, the FLOW data suggests semaglutide could help protect your kidney function long-term.
The trial included patients with eGFR as low as 25 mL/min (stage 4 CKD)—meaning even people with significantly impaired kidney function saw benefits.
Important note: While Ozempic now has an FDA-approved kidney indication, Wegovy (higher-dose semaglutide for weight loss) does not yet have this specific approval—though the underlying drug is the same.
- Novo Nordisk. "Novo Nordisk to discontinue the FLOW kidney outcomes trial for Ozempic® following recommendation from the Independent Data Monitoring Committee." October 2023.
- NEJM. FLOW Trial Full Results. 2024.
- FDA Ozempic Label Update. Kidney indication approval.