Oral Semaglutide and Cardiovascular Risk

A study published September 17, 2026 in Diabetes Therapy found that people newly starting oral semaglutide (Rybelsus) had a lower rate of major cardiovascular events than people newly starting other noninsulin diabetes drugs^[1]. Researchers, most of them Novo Nordisk employees working with a Yale neurologist, compared insurance-claims records for people with type 2 diabetes and existing atherosclerotic cardiovascular disease. Against a pooled comparison group on other glucose-lowering therapies, new oral semaglutide users had 17% and 21% lower risk on two versions of the standard three-point cardiovascular composite^[1]. This explainer walks through what the study actually measured, how it fits next to the randomized trial that already established this drug's cardiovascular benefit, and what the study design does not let you conclude.

What the study compared

The researchers used Optum's Clinformatics Data Mart, a deidentified US insurance-claims database, to build three separate comparisons. In the main analysis, 10,878 new oral semaglutide users were matched against 28,639 people newly started on any other noninsulin glucose-lowering therapy^[1]. Two narrower comparisons followed: oral semaglutide against dipeptidyl peptidase-4 inhibitors, a drug class usually shortened to DPP4is, and oral semaglutide against sodium-glucose cotransporter-2 inhibitors, or SGLT2is. Everyone in the study had type 2 diabetes plus documented atherosclerotic cardiovascular disease, meaning prior heart attack, stroke, or related vascular disease. The team used propensity-score matching, a statistical technique that pairs patients on measured characteristics like age, prior medication use, and comorbidities, to make the two groups being compared look as similar as possible on paper before counting outcomes.

The headline numbers

Against the broad other-therapies group, oral semaglutide use was linked to a 17% lower risk of three-point major adverse cardiovascular events (cardiovascular death, nonfatal heart attack, or nonfatal stroke) and a 21% lower risk on a modified version of that same composite, plus significant reductions in ischemic stroke and all-cause death^[1]. The comparison against DPP4i users specifically showed reductions of 22% and 24% on the same two measures. SGLT2i users showed a similar pattern: 21% and 22%^[1]. The consistency across three separate comparison groups is one reason the authors describe the finding as reinforcing, rather than contradicting, what randomized trials have already shown.

Why this tracks with a real randomized trial

This is not the first evidence that oral semaglutide protects the heart. The SOUL trial, a placebo-controlled randomized trial published in the New England Journal of Medicine in May 2025, randomized 9,650 people with type 2 diabetes and atherosclerotic cardiovascular disease or chronic kidney disease to oral semaglutide or placebo. Over a median follow-up of about 49 months, the semaglutide group had a 14% lower relative risk of major cardiovascular events (hazard ratio 0.86)^[2]. A separate randomized trial, SELECT, tested the injectable form of semaglutide (Wegovy, 2.4 mg weekly) in people with cardiovascular disease and overweight or obesity but no diabetes, and found a 20% relative risk reduction against placebo^[3]. The new observational study did not invent a cardiovascular benefit. It found the same direction of effect in a real-world population using pharmacy and medical claims instead of a controlled trial protocol.

What this study design does not show

An observational cohort study, even a carefully matched one, cannot rule out confounding the way a randomized trial can. Propensity-score matching balances the characteristics researchers measured and recorded in claims data. It cannot balance characteristics nobody measured, such as diet, exercise habits, or why a particular clinician chose one drug over another for a particular patient. A clinician who prescribes a newer, more expensive medicine like oral semaglutide may also be managing that patient's other risk factors more actively, which would make the drug look more protective than it actually is. This pattern, sometimes called confounding by indication, is the standard limitation of every claims-based comparison, and it is exactly what randomized assignment in SOUL and SELECT was designed to eliminate.

It is also worth naming the funding and authorship. Five of the seven authors are Novo Nordisk employees, the company that manufactures and sells semaglutide under the Rybelsus, Ozempic, and Wegovy brand names^[1]. That does not make the numbers wrong. It does mean the study should be read as manufacturer-sponsored real-world evidence that lines up with independent randomized data, not as a standalone, disinterested confirmation.

Where oral and injectable semaglutide differ

Rybelsus is a once-daily tablet; Ozempic and Wegovy are once-weekly injections. All three contain the same active molecule, but they are not interchangeable dose for dose because oral absorption of a peptide drug is far less efficient than a subcutaneous injection. The current US prescribing information for the oral tablet lists two approved uses: improving glycemic control as an adjunct to diet and exercise, and reducing the risk of major cardiovascular events in adults with type 2 diabetes who are at high risk for them^[4]. Like the injectable versions, the oral tablet carries a boxed warning about thyroid C-cell tumors seen in rodent studies, with contraindications for anyone with a personal or family history of medullary thyroid carcinoma or MEN 2 syndrome^[4]. Semaglutide belongs to the GLP-1 receptor agonist class, which also includes tirzepatide, a dual GIP and GLP-1 agonist we cover on its own page.

What this means for patients

None of this is a reason to start or switch a diabetes medication on your own. The literature reports a consistent cardiovascular signal for oral semaglutide across a randomized trial and now a large real-world cohort, in a specific population: adults with type 2 diabetes who already have atherosclerotic cardiovascular disease. Whether that evidence applies to any individual reader, and how it weighs against cost, side effects, and other medications, is a conversation for a prescribing clinician who knows the full history. If you take oral semaglutide or are considering it, the FDA label linked below is the authoritative source on approved uses and warnings, not a claims-database analysis or this article.