Understanding the Connection Between SGLT2 Inhibitors and Atherosclerosis

SGLT2 inhibitors, originally developed to lower blood sugar in type 2 diabetes, have emerged as a cornerstone therapy for reducing cardiovascular risk. Growing evidence indicates that these medications directly and indirectly mitigate atherosclerosis—the progressive buildup of fatty plaque within arterial walls. This expanded review examines how SGLT2 inhibitors work beyond glucose control, the clinical data supporting their vascular benefits, and their place in modern treatment algorithms.

The Pathophysiology of Atherosclerosis: A Brief Overview

Atherosclerosis is a chronic inflammatory disease of the arterial intima. It begins with endothelial dysfunction, often triggered by hyperglycemia, hypertension, dyslipidemia, or smoking. Low-density lipoprotein (LDL) particles infiltrate the subendothelial space, become oxidized, and recruit monocytes that transform into foam cells. Over decades, these foam cells, alongside smooth muscle proliferation and extracellular matrix deposition, form a fibrous plaque. Plaque rupture or erosion is the primary cause of acute coronary syndromes and strokes.

Key risk factors for progression include prolonged hyperglycemia (which generates advanced glycation end products and oxidative stress), hypertension, obesity, systemic inflammation, and insulin resistance. SGLT2 inhibitors have been shown to favorably modify many of these pathways.

Mechanisms of SGLT2 Inhibitors in Atherosclerosis Risk Reduction

Glycemic Control and Beyond

SGLT2 inhibitors block sodium-glucose cotransporter-2 in the proximal renal tubule, reducing glucose reabsorption and promoting glucosuria. HbA1c reductions average 0.5–1.0%, which alone could contribute to slower atherogenesis. However, the cardiovascular benefits observed in trials exceed what would be expected from glucose lowering alone, pointing to multiple non-glycemic mechanisms.

Hemodynamic Effects: Blood Pressure and Volume

These agents induce a mild osmotic diuresis and natriuresis, lowering systolic blood pressure by 3–5 mm Hg. Improved arterial compliance and reduced arterial stiffness have also been documented. Lower blood pressure reduces shear stress on the endothelium, decreasing plaque formation.

Weight Reduction and Metabolic Improvements

Calorie loss from glucosuria leads to a modest 2–4 kg weight loss sustained over time. Reduced visceral adiposity improves insulin sensitivity and lowers circulating free fatty acids, which in turn decreases hepatic very low-density lipoprotein secretion and improves the lipid profile—specifically lowering triglycerides and modestly raising HDL.

Anti-Inflammatory and Antioxidant Actions

Inflammation drives every stage of atherosclerosis. SGLT2 inhibitors reduce levels of high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α). They also suppress activation of the NLRP3 inflammasome, a key mediator of vascular inflammation. Additionally, they reduce oxidative stress by decreasing NADPH oxidase activity and improving mitochondrial function, which protects against endothelial dysfunction.

Improvement in Endothelial Function

Hyperglycemia impairs the bioavailability of nitric oxide, leading to vasoconstriction and pro-thrombotic changes. SGLT2 inhibitors enhance nitric oxide production and reduce endothelin-1 levels, restoring endothelium-dependent vasodilation. This improvement has been demonstrated in brachial artery flow-mediated dilation studies.

Reduction in Uric Acid

These drugs lower serum uric acid by 10–15% through increased urinary excretion. Hyperuricemia is independently associated with atherosclerosis progression; its reduction may contribute to lower cardiovascular risk.

Effects on Adipokine Profile and Ketone Metabolism

SGLT2 inhibitors promote a shift toward fat oxidation and ketone body utilization, particularly β-hydroxybutyrate. Ketone bodies act as a more efficient fuel for the heart and can inhibit histone deacetylases, exerting anti-inflammatory and anti-fibrotic effects. Adiponectin levels increase, while leptin decreases—both changes linked to reduced atherosclerosis.

Clinical Evidence from Major Cardiovascular Outcome Trials

EMPA-REG OUTCOME (Empagliflozin)

Published in 2015, this landmark trial enrolled over 7,000 patients with type 2 diabetes and established cardiovascular disease. Empagliflozin reduced the primary composite endpoint of cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke by 14%. Notably, cardiovascular mortality dropped by 38%, and heart failure hospitalization by 35%. The benefits emerged early within months, suggesting hemodynamic and metabolic effects rather than slow plaque regression.

CANVAS Program (Canagliflozin)

The CANVAS Program, including more than 10,000 participants, showed a 14% reduction in major adverse cardiovascular events (MACE) with canagliflozin. Additional analyses demonstrated a 33% reduction in heart failure hospitalizations. Renal outcomes also improved, with a slower decline in estimated glomerular filtration rate and reduced albuminuria.

DECLARE-TIMI 58 (Dapagliflozin)

With over 17,000 patients, DECLARE-TIMI 58 was the largest SGLT2 inhibitor outcome trial. Dapagliflozin did not meet statistical significance for MACE reduction in the overall cohort (hazard ratio 0.93, p=0.17), but showed a 17% reduction in cardiovascular death or heart failure hospitalization. When analyzing subgroups, patients with established atherosclerotic cardiovascular disease did achieve a significant MACE reduction. This highlights that the magnitude of benefit may depend on baseline risk.

VERTIS CV (Ertugliflozin)

In the VERTIS CV trial, ertugliflozin demonstrated non-inferiority for MACE and reduced heart failure hospitalizations by 30%. The effects on atherosclerosis endpoints were more modest compared to empagliflozin and canagliflozin, possibly due to differences in molecular structure or trial design.

DAPA-HF and EMPEROR-Reduced (Heart Failure Trials)

While these trials enrolled primarily heart failure patients, they reinforce the vascular protective effects of SGLT2 inhibitors. In DAPA-HF, dapagliflozin reduced the composite of worsening heart failure or cardiovascular death by 26% in patients with and without diabetes. The benefits were consistent regardless of atherosclerotic burden.

How Do SGLT2 Inhibitors Compare with Other Antidiabetic Agents for Atherosclerosis?

GLP-1 Receptor Agonists

GLP-1 receptor agonists also reduce MACE, but their mechanisms differ: they promote weight loss, have direct anti-inflammatory effects via GLP-1 receptors on endothelial cells, and lower triglycerides. Some clinical trials suggest GLP-1 agents may have a stronger effect on stroke prevention, whereas SGLT2 inhibitors excel at reducing heart failure and renal endpoints. Combination therapy is often recommended for patients with both atherosclerotic cardiovascular disease and heart failure.

DPP-4 Inhibitors

DPP-4 inhibitors have a neutral effect on cardiovascular outcomes. They do not reduce atherosclerosis events and, in some trials, were associated with a non-significant trend toward increased heart failure hospitalizations. Hence, they are not preferred agents for high-risk patients.

Metformin and Sulfonylureas

Metformin has established cardiovascular safety and some evidence of MACE reduction in overweight patients. Sulfonylureas carry historical concerns about increased cardiovascular mortality, though modern agents appear neutral. Neither provides the consistent multi-organ benefits seen with SGLT2 inhibitors.

Potential Mechanisms Beyond Glycemic Control: A Deeper Dive

Reduction of Arterial Stiffness and Pulse Wave Velocity

Arterial stiffness is an independent predictor of cardiovascular events. In several small studies, empagliflozin and dapagliflozin significantly reduced carotid-femoral pulse wave velocity within 6–12 weeks. The effect may be mediated by reduced oxidative stress and improved vascular smooth muscle cell function.

Improvement in Myocardial Energetics

The heart consumes large amounts of energy, primarily from fatty acids. In diabetes and insulin resistance, myocardial efficiency declines. SGLT2 inhibitors shift metabolism toward ketone bodies, which require less oxygen per ATP produced, improving cardiac efficiency. This may reduce ischemia and vulnerability to plaque rupture in the coronary circulation.

Effects on Sympathetic Nervous System Tone

Chronic sympathetic overactivity accelerates atherosclerosis. SGLT2 inhibitors have been shown to reduce muscle sympathetic nerve activity and lower catecholamine levels, leading to decreased vascular tonicity and reduced afterload.

Modulation of the Renin-Angiotensin-Aldosterone System (RAAS)

These drugs blunt RAAS activation, possibly through increased sodium delivery to the macula densa and altered tubuloglomerular feedback. Reduced angiotensin II and aldosterone levels lower inflammation, fibrosis, and oxidative stress in the vessel wall.

Clinical Implications for Patients with and Without Diabetes

Primary and Secondary Prevention

Current U.S. and European guidelines recommend SGLT2 inhibitors in patients with type 2 diabetes and established atherosclerotic cardiovascular disease (secondary prevention) to reduce MACE. For primary prevention, the benefit is less pronounced but still present, especially in those with heart failure or chronic kidney disease. In patients with heart failure without diabetes, dapagliflozin and empagliflozin are now approved regardless of glycated hemoglobin level.

Considerations for Plaque Burden and Imaging

While large trials used clinical events as endpoints, smaller imaging studies have examined plaque volume. A recent optical coherence tomography study showed that empagliflozin was associated with thicker fibrous caps and less lipid-rich plaques in coronary arteries, suggesting stabilization of vulnerable lesions. This is promising but requires confirmation in larger cohorts.

Safety and Tolerability in Atherosclerosis Populations

Adverse effects include genital mycotic infections (especially in uncircumcised men), volume depletion (particularly in elderly patients on loop diuretics), and rare cases of euglycemic diabetic ketoacidosis. Ketoacidosis can occur even with near-normal glucose levels and may be triggered by illness, surgery, or excessive alcohol. Healthcare providers should counsel patients to stop SGLT2 inhibitors during acute illness or when fasting.

A potential concern is a small increase in lower-limb amputations seen in the CANVAS trial with canagliflozin, though not observed with other agents. Current guidelines recommend using agents other than canagliflozin in patients at high amputation risk (e.g., prior amputation, peripheral artery disease). Furthermore, SGLT2 inhibitors are not recommended in patients with severe renal impairment (eGFR < 30 mL/min/1.73 m²).

Practical Recommendations for Clinicians

  1. Identify candidates: All patients with type 2 diabetes and established atherosclerotic cardiovascular disease, heart failure, or chronic kidney disease should be considered for an SGLT2 inhibitor.
  2. Check renal function before initiating: eGFR should be > 30 mL/min/1.73 m²; dose adjustment may be needed for canagliflozin and ertugliflozin at lower eGFR.
  3. Monitor volume status: Reduce dose of concomitant diuretics if needed, and advise patients to stay hydrated.
  4. Educate on side effects: Inform patients about symptoms of genital infections and the need for prompt treatment. Advise about sick-day rules to prevent ketoacidosis.
  5. Combine with evidence-based therapies: Adding SGLT2 inhibitors to metformin, statins, and RAAS blockers provides additive risk reduction.

Future Directions and Ongoing Research

Several trials are underway to explore the effects of SGLT2 inhibitors on atherosclerosis in patients without diabetes. The DAPASALT and EMPA-BRAIN studies are using coronary computed tomography angiography and carotid ultrasound to directly measure plaque progression. Additionally, research into the gut microbiome suggests these drugs alter microbial composition, which could influence systemic inflammation and lipid metabolism. The coming years will likely expand the role of SGLT2 inhibitors into broader populations.

Conclusion

SGLT2 inhibitors have transformed the management of type 2 diabetes and are now recognized as essential tools in reducing atherosclerotic risk. Their multifaceted mechanisms—including glycemic control, blood pressure reduction, weight loss, anti-inflammation, improved endothelial function, and beneficial metabolic shifts—contribute to a robust reduction in cardiovascular events. The clinical trial evidence supports their use in secondary prevention and in patients with heart failure or chronic kidney disease, with a favorable safety profile when used appropriately. Ongoing research will further delineate the full scope of their vascular protective effects.

For further reading, consult the American Diabetes Association Standards of Care (ADA Standards), the EMPA-REG OUTCOME original publication (New England Journal of Medicine), and the American Heart Association scientific statement on SGLT2 inhibitors (AHA Statement).