Chronic kidney disease (CKD)

Research context

Kidney disease is the dominant non-cardiovascular complication of type 2 diabetes; CKD affects roughly 3 million adults in England (~6% of the adult population), and T2D is the leading cause of end-stage renal disease, responsible for around 30% of dialysis starts. The evidence base advanced through renal secondary analyses of cardiovascular outcome trials (SUSTAIN-6 reduced a nephropathy composite by ~36%, HR 0.64, 95% CI 0.46–0.88; LEADER showed a ~22% reduction) before the dedicated FLOW trial. FLOW randomised 3,533 adults with T2D and CKD (eGFR 25–75 with albuminuria thresholds) to semaglutide 1.0 mg weekly or placebo on top of RAS blockade and, where indicated, SGLT-2 inhibitors, and was stopped early at its planned interim analysis for efficacy on the composite kidney outcome.

Why this matters metabolically

Cardio-renal-metabolic disease is increasingly treated as a unified clinical entity, and GLP-1 receptor agonism addresses CKD through convergent routes: glycaemic improvement reduces glucose-mediated tubular and glomerular injury; the 5–10 mmHg systolic blood-pressure reductions seen across SUSTAIN/SURPASS are haemodynamically relevant; GLP-1 receptors expressed in proximal tubule, collecting duct and mesangial cells may modulate sodium handling, inflammation and oxidative stress; and cardiovascular risk reduction eases the cardiorenal syndrome. Drugs that slow kidney decline alongside cardiovascular events transform the value proposition.

FAQs

What is the FLOW trial and why is it significant?

FLOW was a phase 3 randomised controlled trial of semaglutide 1.0 mg weekly versus placebo in 3,533 adults with T2D and CKD (eGFR 50–75, or 25–<50 with UACR ≥300). It was the first GLP-1 receptor agonist trial to use a major kidney disease event composite as its primary endpoint, and demonstrated a 24% relative risk reduction in that composite over 3.4 years.

What was the composite kidney endpoint in FLOW?

The primary composite comprised onset of kidney failure (sustained eGFR <15, chronic kidney replacement therapy, or transplantation), sustained ≥50% decline in eGFR from baseline, or death from kidney-related causes. The 24% reduction (HR 0.76, 95% CI 0.66–0.88) represents a highly significant and clinically meaningful renal outcome benefit.

Did semaglutide slow the eGFR decline rate in FLOW?

Yes. FLOW reported that semaglutide reduced the annual eGFR slope (rate of kidney function decline) by approximately 1.16 mL/min/1.73 m² per year compared with placebo — a meaningful attenuation of the decline trajectory that, sustained over years, delays kidney failure.

Is semaglutide the only GLP-1 agonist with positive kidney outcomes trial data?

At trial-scale positive endpoints, yes. Semaglutide (FLOW, 2024) is the only GLP-1 receptor agonist that has completed a dedicated kidney outcomes trial with a pre-specified major kidney composite as the primary endpoint. Liraglutide (LEADER) and semaglutide (SUSTAIN-6) showed favourable post-hoc renal secondary data, but none have yet published positive kidney-primary phase 3 data.

How does semaglutide compare to SGLT-2 inhibitors in CKD?

SGLT-2 inhibitors (dapagliflozin in DAPA-CKD, empagliflozin in EMPA-KIDNEY, canagliflozin in CREDENCE) also reduced kidney outcomes by 30–40% in CKD trials, and some showed benefit in non-diabetic CKD. Mechanistically the classes complement each other, and UK guidance increasingly positions them as combination therapy in high-risk CKD with T2D.