GLP-1RAs linked to lower subarachnoid haemorrhage risk in type 2 diabetes studies
Two retrospective studies in type 2 diabetes patients with unruptured intracranial aneurysms linked GLP-1RAs to lower non-traumatic subarachnoid haemorrhage risk. One study also showed lower all-cause mortality over five years.
GLP-1 receptor agonists may reduce the risk of subarachnoid haemorrhage in people with type 2 diabetes, according to two retrospective cohort studies published in 2026. In both studies, the data pointed to a significantly lower risk of non-traumatic subarachnoid haemorrhage among people taking GLP-1RAs, and one study also showed lower all-cause mortality over five years for those on GLP-1RA therapy.
The studies looked at patients with type 2 diabetes who also had unruptured intracranial aneurysms. Researchers compared people who were prescribed GLP-1RAs with those who were not prescribed these drugs over several years of follow-up. One of the studies included more than 24,700 patients with type 2 diabetes and unruptured intracranial aneurysms, and at the three-year mark those on GLP-1RAs had a notably lower incidence of subarachnoid haemorrhage. A second study with matched cohorts of over 2,200 patients reinforced this finding, showing not just reduced subarachnoid haemorrhage risk but also lower all-cause mortality over five years for those on GLP-1RA therapy.
GLP-1RAs are already established in diabetes care for improving glycaemic control and reducing cardiovascular risk. Large meta-analyses of randomised controlled trials have shown that GLP-1RAs can reduce the incidence of stroke by around 15-16 per cent compared with placebo in people with and without diabetes.
The studies said GLP-1RAs appear to support vascular health in a variety of ways. They can improve microvascular function, reduce inflammation and oxidative stress, and help regulate cardiovascular risk factors such as blood pressure and lipid levels. These effects might contribute to a lower probability of aneurysm growth and rupture, which in turn could explain the observed reduction in subarachnoid haemorrhage.
The findings came from observational research, and the studies said association does not prove causation. Because the research looked back at healthcare data rather than assigning people randomly to treatment groups, other factors could explain some of the differences seen, including more intensive medical care or other lifestyle factors. The studies also used large healthcare databases that may not capture all events if patients moved to a different healthcare system or were treated elsewhere.
The reports said the findings merit future prospective trials, particularly for people with type 2 diabetes who also have high cerebrovascular risk or known aneurysms.