What is the ROAR Study?

  The Risk of Aneurysm Rupture (ROAR) Study aims to better understand how likely it is for a brain aneurysm to burst (rupture). We hope to give future patients clearer answers about their own risk and help them make more confident decisions about whether to treat their aneurysm or continue to monitor it through their lifetime. 

To help us create our new risk models, we will anonymously monitor over 20,000 UK patients with brain aneurysms. This sample size is more than double the entire global literature, which means it’s the largest study of its kind in the world. By following these patients through their lifetimes, we can get a better understanding of the risk factors. 

Currently, when patients are found to have an unruptured brain aneurysm, doctors carefully weigh up the likelihood of rupture against the risks of treatment. Available risk prediction models for unruptured aneurysms are limited in their scope and it is challenging to identify which aneurysms will go on to rupture and which will remain stable. By developing more accurate and personalised risk prediction models, the ROAR study will help both patients and doctors make more informed decisions about when and how to treat unruptured brain aneurysms. This will lead to better, more personalised patient care. 

Better Informed Patients: With more precise risk evaluation, patients will have clearer insights into their individual risk of aneurysm rupture, empowering them to make more informed decisions about their healthcare.

Better Treatment Decisions: The study will help ensure that high-risk aneurysms, which require treatment, are treated appropriately. At the same time, it will help prevent unnecessary treatments for low-risk aneurysms, reducing patient exposure to potential complications and risks.

Reducing Anxiety and Uncertainty: With clearer, evidence-based decision-making, patients will feel secure that their treatment and care pathways are designed for them. Knowing that their treatment plan is tailored to their specific risk profile will help to bring peace of mind and reassurance around the risk level and next steps.

Addressing Other Risk Factors: The study will also offer valuable insights into other health factors that could impact aneurysm rupture risk, such as blood pressure control, medications, and hormone replacement therapy. By understanding these additional factors, patients and their doctors can better manage their overall health and reduce the risk of aneurysm rupture.

We will be using medical records to identify patients with an unruptured aneurysms. We will then search national databases for hospital admissions and deaths to identify anyone who had a rupture from their aneurysm after diagnosis. Patients will not be directly involved in the study, and all the work will be carried out using existing medical records.

Your identifiable details will be encrypted and securely transferred to the co-ordinating unit to search the national admissions databases. After this is done your identifiable details will be deleted from their records and only known to your neurosurgery team.

  People who have suffered a bleed from their aneurysm might be less likely to be physically able to provide consent than people who have not suffered a bleed. This means that, if individual consent was required, the study would underestimate the risk of an aneurysm bursting. In turn, this would mean that future decisions for patients would be made based on incorrect information. The ROAR project team takes your data protection and your privacy very seriously and is adhering to the highest standards in patient data handling, ensuing all information is anonymised – meaning your personal details like your name and address are not stored as part of the study, and all data is stored safely within the NHS. 

ROAR has received a favourable opinion from a Research Ethics Committee (REC) (IRAS number 287144) and has support from the Health Research Authority following advice by the Confidentiality Advisory Group (England and Wales) under Regulation 5 of the Health Service (Control of Patient Information) Regulations 2002 to conduct the study without study-specific consent (CAG reference number 21/CAG/0033). This means that the Research Ethics Committee and the Health Research Authority have thoroughly reviewed our processes and are happy that we are adhering to safe practices of data handling, storage and analysis.  

We will also be checking the records held with NHS Digital on patients who have registered as part of the National data opt-out for research. Anyone who has already registered will not be included in the ROAR study. If you wish to register to not have your data included in research then please visit: National data opt-out - NHS Digital. 

If you want to opt of of this study in particular then please inform the Principal Investigator for your neurosurgery unit. Their contact details can be found below. If you cannot find your neurosurgery unit on this this then they are not currently involved in this study.  

This study will carry on for a number of decades. However, first results will be released in the first half of 2026. It is unclear at this point when the results will have an impact on NHS care.

Researchers agree that genetics plays a role in the development, growth and rupture of brain aneurysms. For example, we know that in some families, brain aneurysms have affected multiple generations. Genetics is the science that studies genes and how they are passed from parents to children. It helps us understand why people in the same family might look alike, why some diseases run in families, and how living things grow and change. Genetics is all about how the instructions in our genes shape who we are.

While scientists agree that genetics plays a role, the data and knowledge about which genes cause the risk is limited. By studying genetic factors and the genes involved in brain aneurysms, ROAR-DNA will help identify who needs screening, who may benefit from treatment, and how we might prevent rupture in the future. This will lead to more personalised care, fewer unnecessary scans, and new possibilities for medical treatments—helping patients make more informed and confident decisions about their health.

We’re looking to recruit 6,000 patients to offer us a sample of saliva so we can look at their DNA. All patients and data will be anonymised and their data will be securely stored within the NHS. Patients will need to have a diagnosis of an unruptured aneurysm. We’ll post further details soon about how interested patients can get involved. 

The world-leading study will take a number of years to complete the detailed analysis. Results are scheduled for Autumn 2029.

Doctors have long thought that the shape and blood flow within a brain aneurysm might help predict whether it will burst. However, the current models we use to assess that risk don’t make full use of the detailed information we can get from modern scans. ROAR-FLOW is a major research study that will use advanced imaging and long-term patient follow-up to better understand what makes some aneurysms more dangerous than others.

ROAR-GP will help us improve how we predict aneurysm rupture by linking existing data to GP records. This lets researchers track changes in patients' health over time, such as blood pressure, medications, and lifestyle factors, and explore new risk factors, such as menopause and hormone treatments. By including this broader, real-world information, ROAR-GP will make risk models more accurate and personalised. This means better support for patients and doctors when deciding how to manage unruptured aneurysms, especially in women, who are more commonly affected.