Study Links GLP-1 Treatment Use to Lower Mortality in Patients With Diabetes and Brain Metastases
How do standard diabetes medications relate to outcomes in patients with advanced cancer? While glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are widely used to help manage blood sugar levels, researchers have increasingly begun exploring their associations with a range of health outcomes beyond diabetes. In a newly published study, scientists examined whether prior use of these medications was associated with survival patterns among patients living with both type 2 diabetes and cancer that had spread to the brain.
Note: This article is intended for general information and educational purposes. It summarizes scientific research in accessible language for a broad audience and is not an official scientific press release.
When cancer spreads to the brain, it marks a particularly challenging stage of disease that is often associated with substantial morbidity and mortality. Type 2 diabetes may further complicate outcomes through metabolic and inflammatory mechanisms. Researchers have therefore become interested in whether medications commonly used to treat diabetes might be associated with outcomes in this population.
Among these medications are glucagon-like peptide-1 receptor agonists (GLP-1 RAs), a class of therapies that includes semaglutide, dulaglutide, liraglutide, and related agents such as tirzepatide. Beyond their role in blood sugar management, previous laboratory studies have explored biological pathways involving GLP-1 receptor activation, including pathways related to inflammation and nervous system function. However, clinical evidence evaluating how these medications relate to outcomes in patients with brain metastases remains limited.
To investigate this question, researchers Kuan-Yu Chi, Yu Chang, Junmin Song, Chien-Min Chen, Pang-Shuo Perng, and Hong-Min Lin analyzed data from a large international health-record network. The team was affiliated with the Albert Einstein College of Medicine in New York and several medical and academic institutions in Taiwan, including National Cheng Kung University Hospital, Changhua Christian Hospital, National Chung Cheng University, and Chi-Mei Medical Center. Their findings were published in JAMA Network Open on March 11, 2026. The study examined whether prior GLP-1 RA use was associated with differences in survival among adults diagnosed with both type 2 diabetes and brain metastases.
What the Researchers Investigated
The study focused on adults living with two serious conditions simultaneously: type 2 diabetes and brain metastases. Brain metastases occur when cancer that originated elsewhere in the body spreads to the brain. The researchers sought to determine whether prior GLP-1 RA use was associated with differences in survival outcomes among patients with type 2 diabetes and brain metastases.
Previous laboratory and preclinical studies had explored biological mechanisms involving GLP-1 receptor activation, but evidence from real-world clinical populations remained limited. The authors therefore aimed to assess whether any associations could be observed in a large cohort of patients treated in routine medical practice.
Importantly, this was an observational study. The researchers did not assign treatments or intervene in patient care. Instead, they analyzed existing medical records to evaluate associations between medication use and survival outcomes.
How the Study Was Conducted
The investigators used the TriNetX Global Network, a federated database that contains de-identified electronic health records from 151 healthcare organizations worldwide. The study was approved by the institutional review board of National Cheng Kung University Hospital and followed established reporting standards for observational research.
The researchers identified adult patients diagnosed with cancer, brain metastases, and type 2 diabetes between January 1, 2018, and January 1, 2024. A total of 19,234 eligible patients were identified in the database. For the primary analysis, the researchers focused on patients who either had received a GLP-1 receptor agonist within six months before diagnosis or had not used these medications during the same period.
Among these patients:
- 866 had received a GLP-1 receptor agonist within six months before their diagnosis of type 2 diabetes and brain metastases.
- 11,103 had not used a GLP-1 receptor agonist during the same period.
The GLP-1 RA group included patients prescribed:
- Semaglutide
- Dulaglutide
- Liraglutide
- Tirzepatide
To improve comparability between groups, the researchers performed one-to-one propensity score matching. This statistical method attempts to create groups with similar baseline characteristics, reducing potential bias caused by differences unrelated to medication use.
After matching, 850 GLP-1 RA users were paired with 850 non-users who had similar characteristics. Matching considered numerous variables, including:
- Age
- Sex
- Race and ethnicity
- Primary cancer type
- Bone metastases
- Hypertension
- Heart disease
- Kidney disease
- Smoking history
- Obesity
- Cancer treatments
- Diabetes medications
- Blood sugar measurements
- Kidney function indicators
The primary outcome was all-cause mortality during the three years following the first documented diagnosis of brain metastases. The researchers also predefined two falsification endpoints, seizures and pneumonia, to evaluate whether unmeasured confounding factors might be influencing the results.
What Makes This Study New
Most previous research examining GLP-1 receptor agonists in relation to brain health has been conducted in laboratory settings or preclinical models. Clinical evidence involving patients with brain metastases has remained limited.
The authors highlight that this study provides large-scale observational data drawn from an international health-record network. By using a global database, the researchers were able to analyze a large cohort of patients from multiple healthcare organizations. The study also incorporated propensity score matching and predefined falsification endpoints to address potential confounding and strengthen comparisons between groups.
In addition, the investigators evaluated results across multiple cancer types, multiple GLP-1 RA medications, and comparisons with other diabetes therapies.
Key Findings From the Study
The study found that GLP-1 RA use was associated with significantly lower all-cause mortality during the three-year follow-up period. After propensity score matching, 317 of 850 patients (37.3%) in the GLP-1 RA group died during follow-up, compared with 466 of 850 patients (54.8%) in the non-user group. The corresponding hazard ratio was 0.63 (95% CI, 0.54–0.72; P < .001).
This corresponded to a 37% lower hazard of all-cause mortality during follow-up among GLP-1 RA users.
The association remained generally consistent across several major cancer types, including:
- Lung cancer
- Breast cancer
- Melanoma
The researchers also examined individual GLP-1 RA medications. According to the subgroup analyses, the association with lower mortality was observed among patients using semaglutide and dulaglutide. For liraglutide, the results did not reach statistical significance. There were too few tirzepatide users to generate a reliable estimate.
Additional analyses compared GLP-1 RA users with patients receiving other diabetes medications, including:
- Insulin
- Metformin-containing regimens
- SGLT2 inhibitors
- DPP-4 inhibitors
- Sulfonylureas
- Thiazolidinediones
The observed association remained generally consistent across these comparisons. Importantly, when the researchers examined their predefined falsification endpoints, seizures and pneumonia, the rates were comparable between the two groups.
Authors’ Conclusions
The authors concluded that GLP-1 RA use was associated with significantly lower all-cause mortality among patients with type 2 diabetes and brain metastases. They noted that the association appeared generally consistent across multiple subgroup analyses.
The researchers also observed that these findings are consistent with earlier laboratory studies that explored biological mechanisms involving neuroinflammation, blood-brain barrier integrity, oxidative stress, and mitochondrial function. However, they emphasized that their study design does not allow conclusions about cause and effect.
The authors highlighted several limitations:
- The retrospective design limits causal inference.
- The database did not contain sufficient information for dose-response analyses.
- Cancer-specific mortality could not be evaluated.
- Details regarding some treatments were unavailable.
- Many non-users were excluded during matching, which may affect generalizability.
- Most participating institutions were academic medical centers, which may not fully represent all clinical settings.
Because of these limitations, the researchers stated that future prospective studies will be needed to further examine the relationship between GLP-1 receptor agonists and outcomes in cancer populations.
Understanding the Broader Context
This study adds observational data to the scientific literature examining outcomes among patients with cancer, brain metastases, and type 2 diabetes. While previous work has explored potential biological pathways involving GLP-1 receptor activation, clinical evidence in patients with brain metastases has remained limited. The current analysis provides additional real-world data from a large international health-record network and contributes to ongoing research in this area.
Conclusion
One notable finding was the magnitude of the observed association. After matching patients with similar clinical characteristics, GLP-1 RA users had a 37% lower hazard of all-cause mortality during follow-up (HR 0.63). The association remained generally consistent across patients with brain metastases originating from lung cancer, breast cancer, and melanoma. In subgroup analyses, semaglutide (HR 0.38) and dulaglutide (HR 0.75) were associated with lower mortality, whereas the findings for liraglutide did not reach statistical significance.
In summary, this large international study reported an association between prior GLP-1 RA use and lower all-cause mortality during three years of follow-up among adults with type 2 diabetes and brain metastases. What remains uncertain is whether the observed association reflects a direct effect of the medications, differences that could not be fully measured within the dataset, or a combination of factors. As the authors note, prospective studies will be necessary to further investigate these findings and clarify their interpretation.
The information in this article is provided for informational purposes only and is not medical advice. For medical advice, please consult your doctor.
Reference:
Chi KY, Chang Y, Song J, Chen CM, Perng PS, Lin HM. GLP-1 Receptor Agonist Use and Survival Among Patients With Type 2 Diabetes and Brain Metastases. JAMA Network Open. 2026;9(3):e261311. DOI: https://doi.org/10.1001/jamanetworkopen.2026.1311
