Antidiabetic medications and cardiovascular risk

The relationship between antidiabetic medications and cardiovascular risk has become a cornerstone of type 2 diabetes mellitus treatment, because it is no longer acceptable to assess an agent solely by its ability to lower blood glucose. For many years, treatment followed an almost exclusively glucose-centric objective: lowering glycated hemoglobin, limiting progression of microvascular disease, and correcting chronic hyperglycemia. Over time, however, it became clear that the true prognostic burden of type 2 diabetes depends largely on its macrovascular complications, namely myocardial infarction, ischemic stroke, heart failure, cardiovascular death, and progression of cardiorenal disease. Modern antidiabetic medications must therefore also be judged by how they alter the fate of the heart and vascular system, not only by their biochemical effect on blood glucose.

This paradigm shift was made possible by major cardiovascular outcome trials, randomized studies designed to determine whether a glucose-lowering class was cardiovascularly safe or even capable of providing a prognostic benefit. These studies produced a much more complex picture than the traditional one. Some classes proved essentially neutral for major cardiovascular events. Others showed specific advantages in atherosclerotic disease. Still others particularly clearly modified the risk of hospitalization for heart failure and the patient's cardiorenal trajectory. Consequently, in contemporary practice, medication selection in type 2 diabetes must consider which cardiovascular phenotype is present: predominant atherosclerosis, heart failure, diabetic kidney disease, obesity with high cardiometabolic risk, or vulnerability to hypoglycemia and arrhythmias.

Type 2 diabetes mellitus is a state of chronic metabolic dysfunction that simultaneously accelerates atherogenesis, endothelial dysfunction, vascular inflammation, oxidative stress, thrombogenicity, myocardial fibrosis, ventricular remodeling, and microvascular damage. Persistent hyperglycemia promotes the formation of advanced glycation end products, impairs nitric oxide bioavailability, increases vascular stiffness, and contributes to a proinflammatory environment that makes atherosclerotic plaques more unstable. This is compounded by insulin resistance, visceral obesity, hypertriglyceridemia, reduced high-density lipoprotein cholesterol, hypertension, and metabolic dysfunction-associated steatotic liver disease: an entire biological context that multiplies the risk of vascular events.

The diabetic heart is exposed not only to ischemic risk. Patients with type 2 diabetes often develop a specific vulnerability to heart failure due to varying combinations of microangiopathy, myocardial lipotoxicity, altered cardiac energy metabolism, interstitial fibrosis, neurohormonal activation, and hemodynamic overload. Consequently, the patient may develop not only myocardial infarction and stroke, but also heart failure with or without reduced ejection fraction. This is essential because it explains why antidiabetic medications cannot be considered equivalent: some classes mainly influence atherothrombotic risk, others have a more pronounced effect on heart failure, and still others remain neutral.

Hypoglycemia is also relevant to cardiovascular risk. Treatment that increases severe hypoglycemic episodes may promote catecholamine surges, arrhythmias, ischemia, hemodynamic instability, and worse outcomes, especially in older patients, those with coronary artery disease, or those with autonomic neuropathy. This leads to a central principle of modern diabetology: a cardiovascularly favorable medication is not only one that reduces myocardial infarction or cardiovascular death, but also one that controls diabetes without adding iatrogenic hemodynamic and arrhythmic risks.

The final concept is therefore that cardiovascular risk in type 2 diabetes does not depend on a single mechanism and cannot be corrected by a single parameter. The ideal medication must fit into this complex network by improving blood glucose, weight, kidney function, hemodynamic load, cardiac metabolism, and hypoglycemia safety. This integrated perspective is the basis of the modern hierarchy of antidiabetic medication classes in cardiovascular care.

Cardiovascular risk assessment should precede prescribing, not follow it. The first step is to determine whether the patient has documented atherosclerotic cardiovascular disease, namely a history of myocardial infarction, acute coronary syndrome, coronary or peripheral revascularization, ischemic stroke, transient ischemic attack, or symptomatic peripheral artery disease. In this setting, antidiabetic therapy becomes part of secondary prevention, and the selection criterion shifts toward agents with demonstrated benefit on major cardiovascular events.

The second step is to determine whether heart failure coexists, even without overt coronary artery disease. A history of hospitalization for heart failure, reduced exercise tolerance, edema, increased natriuretic peptides, or echocardiographic evidence of systolic or diastolic dysfunction profoundly changes the strategy. In this phenotype, medications that reduce the risk of heart-failure hospitalization assume a priority that may even outweigh pure glycemic efficacy.

The third element is coexisting chronic kidney disease, because the kidney and heart share an extremely close pathogenic relationship in diabetes. Albuminuria, reduced estimated glomerular filtration rate, progression of kidney disease, and cardiorenal volume overload make medications that protect both organs simultaneously particularly valuable. For this reason, the modern interpretation of cardiovascular risk in diabetes is actually a cardiorenal interpretation.

Finally, obesity, age, frailty, hypoglycemia risk, history of pancreatitis, gastrointestinal tolerability, susceptibility to genitourinary infections, blood pressure, volume status, and the overall therapeutic context must be considered. A person with visceral obesity and high atherosclerotic risk does not require the same medication as an older patient with heart failure, reduced glomerular filtration, and frequent hypoglycemia. The correct cardiometabolic choice is always phenotype-dependent.

• Presence of clinically manifest atherosclerosis.
• Presence of heart failure or a high risk of hospitalization.
• Presence of chronic kidney disease with or without albuminuria.
• Risk of hypoglycemia, body weight, age, frailty, and tolerability.

Sodium-glucose cotransporter 2 inhibitors have profoundly changed the treatment of type 2 diabetes because they demonstrated that an antidiabetic medication can improve cardiovascular prognosis through mechanisms extending well beyond blood glucose reduction. By acting on the renal proximal tubule, these agents reduce glucose and sodium reabsorption, promoting glycosuria, natriuresis, and modulation of tubuloglomerular feedback. Clinically, this translates into reduced volume overload, lower intraglomerular pressure, a slight reduction in blood pressure, modest weight loss, and improved cardiorenal physiology.

The EMPA-REG OUTCOME trial showed that, in patients with type 2 diabetes and established cardiovascular disease, empagliflozin reduced the risk of the composite endpoint of cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke, with a particularly strong signal for cardiovascular death and hospitalizations for heart failure. CANVAS and DECLARE-TIMI 58 subsequently strengthened the class profile, although populations and the magnitude of benefit for individual endpoints differed. The clinical message was very clear: sodium-glucose cotransporter 2 inhibitors are not merely cardiovascularly safe; they are protective in specific phenotypes.

In practical terms, the most robust and reproducible benefit of this class concerns heart failure and the cardiorenal trajectory. Consequently, in patients with established heart failure or chronic kidney disease, this class now tends to occupy a priority position. Its benefit appears partly independent of blood glucose reduction, explaining why these medications may remain useful even when their glucose-lowering efficacy diminishes as glomerular filtration declines.

The other side of the equation is selective safety. These medications require caution in patients predisposed to euglycemic diabetic ketoacidosis, dehydration, hypotension, genital fungal infections, or circumstances involving reduced food intake and acute physiological stress. Their cardiovascular value should therefore never be interpreted as an automatic prescription detached from the clinical context. The class is highly potent prognostically, but must be integrated with therapeutic education, temporary discontinuation during acute illness, and appropriate patient selection.

Overall, however, sodium-glucose cotransporter 2 inhibitors currently represent the category with the strongest rationale when type 2 diabetes is accompanied by heart failure, diabetic kidney disease, or a need for structural cardiorenal protection.

Glucagon-like peptide 1 receptor agonists have opened a second major pathway of cardiovascular protection in type 2 diabetes. Unlike sodium-glucose cotransporter 2 inhibitors, their distinctive effect is more strongly linked to reducing atherothrombotic risk, weight loss, improving the blood-pressure profile, and favorably modulating multiple components of cardiometabolic risk. These medications increase glucose-dependent insulin secretion, reduce inappropriate glucagon secretion, slow gastric emptying to varying degrees, and increase satiety. Their cardiovascular impact, however, cannot be explained solely by glycemic control or weight loss, but also appears to involve vascular, anti-inflammatory, and antiatherogenic effects.

The LEADER trial demonstrated that liraglutide reduces major cardiovascular events, namely the composite of cardiovascular death, nonfatal myocardial infarction, and nonfatal stroke, in high-risk patients. SUSTAIN-6 also documented cardiovascular benefit with semaglutide, while REWIND showed that dulaglutide can reduce cardiovascular risk in a population less exclusively selected for secondary prevention and therefore closer to real-world clinical practice. These data moved the class into a first-line strategic position for patients with type 2 diabetes and atherosclerotic cardiovascular disease or very high risk.

Clinically, glucagon-like peptide 1 receptor agonists are particularly valuable when obesity, high atherosclerotic risk, a need for substantial glycated hemoglobin reduction, and a desire to avoid hypoglycemia coexist. Their ability to promote weight loss often makes them more strategic than classes that are glycemically effective but weight-neutral or unfavorable.

Tirzepatide, a dual glucose-dependent insulinotropic polypeptide and glucagon-like peptide 1 receptor agonist, has joined this therapeutic area. Its metabolic profile is particularly potent for both blood glucose and weight. In cardiovascular terms, the SURPASS-CVOT trial showed noninferiority to dulaglutide for the composite of cardiovascular death, myocardial infarction, or stroke in patients with type 2 diabetes and atherosclerotic cardiovascular disease, without demonstrating superiority for the same primary endpoint. Tirzepatide therefore currently stands as a highly effective cardiometabolic option for glycemic and weight outcomes, but its cardiovascular positioning must be interpreted in light of comparison with an active agent that is already cardioprotective, rather than with placebo.

The main limitations of these therapies remain gastrointestinal tolerability, the need for gradual titration, caution in patients with significant gastroparesis, and management of the balance between efficacy and clinical acceptability. Despite this, incretin-based therapies are among the most rational pillars of modern cardiovascular medicine in patients with type 2 diabetes, obesity, and atherosclerotic risk.

Metformin retains an important role in the treatment of type 2 diabetes because of its low hypoglycemia risk, low cost, good initial efficacy, and extensive clinical experience. Historically, it was also considered foundational because of the potential cardiovascular benefit observed in early studies, but its position has changed in the contemporary paradigm: it remains very useful, but is no longer sufficient by itself to define a cardiorenal strategy. In a patient with atherosclerosis, heart failure, or kidney disease, metformin is often a basic supportive therapy rather than the true determinant of prognostic benefit.

Pioglitazone requires more nuanced reasoning. As a peroxisome proliferator-activated receptor gamma agonist, it improves insulin resistance and alters adipose and hepatic metabolism. The PROactive trial showed a favorable signal for some secondary macrovascular endpoints, suggesting that the medication may provide an atherosclerotic benefit in selected phenotypes with high insulin resistance. However, edema, weight gain, and the risk of worsening or precipitating heart failure greatly limit its use. Pioglitazone is contraindicated in patients with current or prior heart failure; outside that condition, it is not a medication that must be excluded absolutely for cardiovascular reasons, but an agent to be used only after careful assessment of the clinical phenotype.

Dipeptidyl peptidase 4 inhibitors have demonstrated a predominantly neutral cardiovascular profile. TECOS with sitagliptin, EXAMINE with alogliptin, and CARMELINA with linagliptin showed substantial cardiovascular safety without demonstrating a reduction in atherothrombotic events. Saxagliptin is different because SAVOR-TIMI 53 found an increase in hospitalizations for heart failure, a signal that requires caution, especially in patients with preexisting heart failure or a high risk of developing it. The class therefore retains a role in patients who require simplicity, oral administration, and a low probability of hypoglycemia, but it is not the first choice when the principal decision point is cardiovascular protection.

Sulfonylureas occupy an intermediate and historically more controversial position. Concerns about cardiovascular toxicity related mainly to older generations and observational data that were difficult to interpret. More recent studies, including CAROLINA for glimepiride, have reduced the perception of an inevitable excess of major cardiovascular events, instead showing substantial neutrality compared with the active comparator. The real problem with this class, however, remains the increased risk of hypoglycemia and possible weight gain, two factors that may indirectly worsen the cardiovascular profile of a frail patient. Sulfonylureas are therefore now less attractive when alternatives with a low hypoglycemia risk and documented cardiorenal benefit are available.

Insulin cannot be interpreted simplistically as “good” or “bad” from a cardiovascular perspective. The ORIGIN and DEVOTE trials showed substantial cardiovascular neutrality for glargine and degludec, respectively, with differences mainly in hypoglycemia risk rather than major cardiovascular events. In clinical practice, insulin remains indispensable when rapid control is required, blood glucose is very high, or beta-cell reserve is severely compromised. In patients at high cardiovascular risk, however, a strategy centered only on insulin without medications with demonstrated cardiorenal benefit may be prognostically less contemporary.

In patients with manifest atherosclerosis, namely a history of myocardial infarction, ischemic stroke, or peripheral artery disease, treatment tends to favor glucagon-like peptide 1 receptor agonists with documented benefit on major cardiovascular events, with or without a sodium-glucose cotransporter 2 inhibitor if cardiorenal indications coexist. In this phenotype, treatment should not be limited to blood glucose, but integrated with a high-intensity statin, antiplatelet therapy when indicated, blood-pressure control, and smoking cessation. The antidiabetic medication becomes one component of secondary prevention.

In patients with heart failure, especially those with a history of hospitalization or clinical evidence of congestion, sodium-glucose cotransporter 2 inhibitors assume particular priority. In this setting, incretin-based therapy may be useful for glycemic control and weight loss, but the medication that most directly changes hospitalization risk and cardiorenal dynamics remains the sodium-glucose cotransporter 2 inhibitor. Pioglitazone is contraindicated in patients with current or prior heart failure, whereas saxagliptin requires caution.

In patients with cardiorenal disease, namely diabetes associated with reduced glomerular filtration, albuminuria, and high cardiovascular risk, the most effective approach is often combinatorial: metformin when possible, a sodium-glucose cotransporter 2 inhibitor for cardiorenal protection, and, if needed for additional glycemic control and atherosclerotic benefit, addition of a long-acting glucagon-like peptide 1 receptor agonist with documented cardiovascular benefit. This framework reflects the current concept of multitarget therapy.

In patients with clinically significant obesity and high cardiovascular risk, incretin receptor agonists and tirzepatide acquire additional value because weight loss itself becomes a cardiovascular intervention. Reducing visceral adiposity, blood pressure, metabolic dysfunction-associated steatotic liver disease, and systemic inflammation may alter the risk trajectory more profoundly than a simple reduction in glycated hemoglobin achieved with weight-neutral medications.

In older, frail patients with a history of falls or arrhythmic vulnerability, the dominant criterion may become avoidance of hypoglycemia. In this case, classes such as sulfonylureas and complex insulin regimens become less attractive, while medications with a low hypoglycemia risk are preferable, provided they are compatible with kidney function, nutritional status, and overall tolerability.

The cardiovascular risk associated with an antidiabetic medication depends not only on trials of hard endpoints, but also on its indirect effects on variables that influence prognosis. The first is hypoglycemia. A medication that exposes patients to severe hypoglycemic episodes may precipitate ischemic, arrhythmic, or traumatic events, especially in older patients, those with coronary artery disease, or those with autonomic neuropathy. Thus, the advantage of classes such as metformin, sodium-glucose cotransporter 2 inhibitors, glucagon-like peptide 1 receptor agonists, tirzepatide, and dipeptidyl peptidase 4 inhibitors also includes indirect cardiovascular safety.

The second variable is body weight. Medications that promote weight gain, such as insulin and sometimes sulfonylureas or pioglitazone, may worsen cardiometabolic risk if used without a clear compensatory rationale. Conversely, incretin-based therapies and sodium-glucose cotransporter 2 inhibitors can reduce body weight or at least prevent further adipose burden, with favorable effects on blood pressure, obstructive sleep apnea, inflammation, and cardiac function.

The third variable is blood pressure and volume management. Sodium-glucose cotransporter 2 inhibitors often provide a modest but clinically useful blood-pressure and decongestive benefit. This effect should be leveraged in patients with heart failure or volume overload, but managed carefully in frail individuals or those at risk of hypotension, especially if they are already receiving diuretics.

The fourth is treatment adherence. A highly effective medication that is poorly tolerated, costly, or perceived as excessively complex may fail in real life. From a cardiovascular perspective, even the best agent loses prognostic effectiveness if the patient discontinues it, takes it irregularly, or does not understand how to manage it during intercurrent illness. Cardiovascular medicine in diabetes is therefore inseparable from therapeutic education.

No antidiabetic medication alone corrects the entire cardiovascular risk of a patient with type 2 diabetes. Even when an agent with demonstrated benefit on major cardiovascular events is used, outcomes depend on integration with all other pillars of prevention. Statins, blood-pressure control, inhibition of the renin-angiotensin-aldosterone system when indicated, antiplatelet therapy in appropriate settings, smoking cessation, physical activity, a Mediterranean diet, weight reduction, and treatment of chronic kidney disease remain indispensable.

The antidiabetic medication should therefore be viewed as part of an integrated cardiovascular strategy. In a patient with prior myocardial infarction and obesity, for example, a glucagon-like peptide 1 receptor agonist or tirzepatide may act synergistically with a statin and antihypertensive therapy. In a patient with heart failure and albuminuria, a sodium-glucose cotransporter 2 inhibitor fits within a therapeutic network that includes blood-pressure control, kidney protection, and volume monitoring. In an older, frail patient, selection may focus on hypoglycemia safety and treatment simplification.

This means that the correct question is not simply which medication “is good for the heart” in the abstract, but which medication best fits the patient's actual cardiovascular profile. Personalization is therefore not an organizational preference, but the most rigorous form of evidence-based medicine. Modern guidelines converge precisely on this point: in patients with type 2 diabetes, pharmacological treatment must always be built around cardiovascular and renal comorbidities, not blood glucose alone.

Medication selection now has concrete prognostic value. The decision is no longer only how much glycated hemoglobin will decrease over the next few months, but how to influence the risk of myocardial infarction, stroke, cardiovascular death, hospitalization for heart failure, and progression of cardiorenal syndrome over the following years. This transformation has brought diabetologists and internists much closer to cardiologists and nephrologists, because prescribing antidiabetic medication has become an act of preventive cardiovascular medicine.

In practical terms, antidiabetic classes can now be placed along a spectrum. Some are predominantly cardioprotective in specific phenotypes, such as sodium-glucose cotransporter 2 inhibitors for heart failure and cardiorenal protection and some glucagon-like peptide 1 receptor agonists for atherosclerosis and reduction of major cardiovascular events. Others are mainly cardiovascularly neutral, meaning not harmful but not clearly protective for hard endpoints, such as many dipeptidyl peptidase 4 inhibitors, basal insulin, and glimepiride in contemporary data. Still others require careful selection because their metabolic profile may be favorable but the cardiovascular context may limit use, as with pioglitazone.

Prognosis also depends on when the choice is made. Introducing medications with cardiorenal value too late means losing a clinically relevant window of protection. Similarly, continuing to use less strategic agents for a prolonged period after a patient develops atherosclerosis, heart failure, or chronic kidney disease means remaining anchored to an outdated model of diabetology. Modern treatment of type 2 diabetes therefore requires continuous updating, critical interpretation of trials, and the ability to integrate medication selection into the natural history of the disease.

In conclusion, the relationship between antidiabetic medications and cardiovascular risk has transformed diabetes treatment into an increasingly prognostic and less exclusively glycemic discipline. The best medication is not the one that lowers glycated hemoglobin the most in absolute terms, but the one that, in the individual patient, improves metabolic control, safety, body weight, heart protection, and kidney protection together.