A study published in The BMJ reveals that incorporating the GLP-1 receptor agonist tirzepatide—sold under the brand name Mounjaro—into standard medical management for individuals with type 2 diabetes and pre-existing heart disease cuts the likelihood of major cardiovascular events by 32%.
To assess how incorporating tirzepatide into routine care influences heart health, researchers examined medical records from two American health insurance claims repositories covering the timeframe from May 2022 to May 2025. The study included patients with type 2 diabetes, a body mass index of at least 25, and established heart disease, comparing their outcomes to patients starting sitagliptin, a diabetes drug chosen as a neutral placebo proxy.
The analysis covered 52,971 individuals with an average age of 70 years, of whom 51% were female. Among the participants, 35,353 started tirzepatide and 17,618 started sitagliptin. At the one-year mark, the risk of major adverse cardiovascular events—a combined measure of heart attack, stroke, and death from any cause—was 2.9% in the tirzepatide group compared with 4.4% in the sitagliptin group.
Cardiovascular Outcomes and Heart Attack Risk Reductions
When breaking down individual components of major adverse cardiovascular events, tirzepatide showed a specific benefit for preventing heart attacks. According to the study findings, the drug was associated with a 33% lower risk of heart attack compared with sitagliptin. However, ischaemic stroke rates showed no meaningful difference between the two treatment groups.
Researchers estimate that for every 70 patients who start taking tirzepatide, one case of a major cardiovascular event is prevented. The study also calculated that one death from any cause is prevented for every 122 patients starting the medication.
Impact on Hospital Admissions and Infections
Beyond cardiovascular endpoints, the claims database analysis tracked secondary outcomes including hospitalizations and mortality related to infections. Infections requiring hospital admission were lower among patients taking tirzepatide, yielding one prevented hospital admission for every 48 patients treated.
Additionally, infection-related deaths decreased in the tirzepatide cohort, with one infection-related death prevented for every 200 patients. The researchers accounted for variables such as age, sex, race, body mass index, previous heart problems, concurrent chronic conditions, and medication use by employing a statistical technique called propensity score overlap weighting to balance the groups.
Study Limitations and Expert Perspectives
While the observational study provides real-world data on routine clinical care, the authors acknowledged several limitations. The follow-up period spanned up to one year, which may underestimate long-term cardiovascular and safety effects. The study design also carried a risk of possible misclassification of treatment duration or outcomes, and findings may not directly apply to other healthcare systems or patients without established cardiovascular disease.
A linked editorial published alongside the research noted that the study offers a transparent estimate of what initiating tirzepatide can achieve in routine care, but it does not establish a mortality indication or define the best sequence for cardiometabolic therapy. Editorialists emphasized that longer follow-up, randomized comparisons, and further evaluation of additive benefits on contemporary background treatment remain necessary. Furthermore, the editorial highlighted that cardiovascular efficacy cannot benefit populations if cost, authorization barriers, supply shortages, and treatment discontinuation prevent sustained use.
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