Adults with type 2 diabetes who raised their Ozempic dose from 1 mg to 2 mg had a 6% lower relative risk of death, heart attack, or stroke than those who switched to Mounjaro, according to a real-world analysis that Novo Nordisk announced on Sept. 29 at the European diabetes meeting in Milan. Novo Nordisk makes Ozempic and funded the work. Eli Lilly makes Mounjaro.
The finding speaks to a real decision many patients face. When blood sugar is not yet at goal on Ozempic 1 mg, doctors often choose between a higher dose of the same drug and a switch to tirzepatide, the active ingredient in Mounjaro.
The difference is small, however, and the study compared groups of patients who were not randomly assigned. That leaves room for hidden differences between the groups to explain part or all of the gap.
A 6% Difference Drawn From Insurance Claims
The study, called COMPETE SWITCH CV, used a large U.S. insurance claims database with linked lab results covering January 2018 through September 2025. Researchers identified 636,525 adults with type 2 diabetes taking weekly semaglutide 1 mg.
The heart analysis compared 185,705 adults who increased to 2 mg with 23,104 who switched to tirzepatide at doses up to 15 mg. The outcome was combined death from any cause, heart attack, and stroke. After adjustment, patients who switched had a 6% higher risk than those who raised their dose, a hazard ratio of 1.06 with a 95% confidence range of 1.04 to 1.08, HCPLive reported.
A smaller group with more lab data showed a similar pattern. The company did not release absolute event rates, so readers cannot yet see how many heart attacks, strokes, or deaths the 6% figure represents.
Most patients never changed course. One year after their first 1 mg fill, 67.2% remained on that dose, 29.2% had moved to 2 mg, and 3.6% had switched to tirzepatide. By about two years, 57.4% remained on 1 mg, 36.9% had moved up, and 5.7% had switched.
This is the second COMPETE SWITCH report. An earlier analysis of the same population, presented at the American Diabetes Association meeting in June, looked at blood sugar and weight rather than heart events.
Reasons the Comparison May Be Tilted
Novo Nordisk itself noted that the results may reflect residual unmeasured confounding and that causal relationships cannot be established. In practice, patients who switch drugs may differ from those who simply raise a dose in ways a database cannot see, such as side effects, how well they responded, or how sick they were.
Dosing is another concern. Tirzepatide starts at 2.5 or 5 mg, and only about 31% of switchers reached 10 mg or higher during follow-up. The comparison may therefore include many patients who never reached a full tirzepatide dose.
Scale also matters. With more than 200,000 patients, even small differences can reach statistical significance, and a result can be real on paper yet too small to change care. Safety outcomes were not assessed. Claims data can also leave out people with gaps in insurance coverage, which may limit how well the results apply to underserved patients.
Randomized evidence offers a different kind of comparison. On Aug. 28, the FDA approved Mounjaro to lower heart attack and stroke risk in adults with type 2 diabetes, based on a head-to-head trial against dulaglutide. In that trial, tirzepatide had an 8% lower rate of major heart events, a result that met the goal of being no worse than dulaglutide but was not statistically significant as a superiority finding, Lilly reported. Both Ozempic and Mounjaro now carry cardiovascular indications, and this analysis does not replace trial-based evidence.
Michael Radin, M.D., Novo Nordisk's executive medical director, said the data may help clinicians facing a common question: "whether to increase the dosage or switch to another therapy."
Kathryn S. Tierney, a family nurse practitioner with Middlesex Health in Connecticut, called treatment intensification "a common challenge we face in clinical practice," particularly for patients who tolerate their current drug but have not reached their goals. Her comment appeared in Novo Nordisk's announcement, so it is not an independent review of the data.
Practical Meaning for People on Ozempic 1 mg
For patients, this analysis is one data point in a conversation, not a reason to insist on one drug. People already doing well on either medication have no reason from this study to change. Any change in dose or drug should be made with a prescriber.
Those most affected are adults with type 2 diabetes who have not reached their blood sugar goal on 1 mg and who also have heart disease or high heart risk. For them, reasonable questions include how each option fits their heart history, which side effects they have tolerated, and whether their insurer covers both drugs.
Cost can decide the matter. Insurers often prefer one GLP-1 drug over another, and a switch may require a new prior authorization. Asking the pharmacy or insurer about coverage before a visit can prevent delays.
MedicalDaily has also examined an earlier claims study of tirzepatide and heart events and the limits of that design. The COMPETE SWITCH results have been presented at a meeting but not yet published in a peer-reviewed journal. Until full publication with absolute risks, or independent and randomized comparisons, the choice should rest on individual heart risk, tolerance, and coverage.
Key Questions Answered
What did the Novo Nordisk analysis find? Adults with type 2 diabetes who raised Ozempic from 1 mg to 2 mg had a 6% lower relative risk of death, heart attack, or stroke than those who switched to Mounjaro.
Who funded the research? Novo Nordisk, the maker of Ozempic, funded and announced the analysis.
Does this prove Ozempic protects the heart better than Mounjaro? No. It is a retrospective claims study that shows an association, and the company acknowledged that residual confounding cannot be ruled out.
Were absolute risks reported? No. The announcement did not include absolute event rates, so the real-world size of the difference is unclear.
Should I switch or change my dose? Not based on this study alone. Talk with your prescriber about your heart risk, side effects, and insurance coverage.
Is Mounjaro approved for heart protection? Yes. The FDA approved it on Aug. 28 to lower cardiovascular risk in adults with type 2 diabetes.
Published by Medicaldaily.com
