Consensus-Driven Outcomes for Aneurysmal Subarachnoid Hemorrhage Research

In the February 2026 issue of Stroke, Andersen et al. published an International Position Statement that aimed to standardize outcome selection in aneurysmal subarachnoid hemorrhage (aSAH) research. The article addresses a longstanding challenge in the field: substantial variability in how outcomes are measured and reported across clinical trials, which has limited the ability to compare interventions and synthesize evidence. Prior systematic review work identified 285 unique outcome measures across 129 published aSAH studies, underscoring the lack of consistency in outcome reporting.

To address this gap, investigators sought to establish a consensus-derived core outcome set (COS) for aSAH research. A COS is a standardized collection of outcomes recommended for consistent assessment across clinical studies within a particular disease area. The goal is to improve comparability between trials while ensuring research remains patient-centered and clinically meaningful.

The consensus process was informed by two international prioritization surveys involving 239 participants from more than 25 countries across 6 continents. Stakeholders included patients, caregivers, clinicians, researchers, and representatives from aSAH-related organizations. Using OMERACT consensus methodology, investigators conducted a hybrid in-person and virtual workshop alongside the International Subarachnoid Hemorrhage Conference in 2023. A total of 69 participants contributed, including individuals with lived aSAH experience, healthcare professionals, and researchers.

6 Core Domains Identified for Future aSAH Trials
Consensus was achieved on 6 key health domains. 4 were designated as core domains for all future aSAH trials: cognition and executive function, functional outcomes, health-related quality of life (HRQoL), and survival. Two additional domains—delayed cerebral ischemia (DCI) with cerebral infarction (CI), and rebleeding with aneurysm obliteration—were identified as core domains in specific clinical circumstances, particularly studies focused on acute management. Here’s a deeper look at each of these domains:

• Cognition and executive function encompassed attention, memory, executive functioning, language, perception, and processing speed.
• HRQoL was broadly defined to include physical, psychological, social, and financial well-being, as well as the ability to live a fulfilling and purposeful life.
• Functional outcomes included activities of daily living, instrumental independence, social participation, mobility, return to work, and recovery toward baseline functioning.
• Survival was stated as being alive at a measured point in time after hemorrhage.
• Rebleeding and aneurysm obliteration referred to a distinct second episode of bleeding from a cerebral aneurysm occurring before, during, or after treatment, as well as complete angiographic occlusion of the aneurysm following interventions such as clipping or coiling.
• DCI and CI were defined using previously established consensus criteria. DCI involved new focal neurological deficits or decreased consciousness not attributable to other causes, whereas cerebral infarction required radiographic evidence on CT or MRI within 6 weeks of hemorrhage.

Emphasis on Patient-Centered Recovery
A notable feature of the initiative was the emphasis placed on patient-centered outcomes that extend beyond traditional survival and disability metrics. One of the study’s major strengths was the prominent involvement of individuals with lived aSAH experience throughout the planning, prioritization, and consensus process. Investigators emphasized that patients and caregivers broaden the research agenda by highlighting outcomes that affect long-term recovery but are often overlooked in traditional trial design.

The study also benefited from the rigorous and internationally recognized OMERACT framework for consensus development, which strengthened the credibility and methodological consistency of the consensus process.

Remaining Challenges and Future Directions
The authors acknowledged limitations, including underrepresentation of low- and middle-income countries, which may affect generalizability. Additionally, although the work establishes what should be measured, it does not fully address implementation challenges, including the increased cost and complexity associated with assessing patient-centered outcomes such as cognition and quality of life.

Ultimately, this International Position Statement represents an important step toward more standardized, patient-informed aSAH research. By prioritizing outcomes that reflect both survival and quality of recovery, the proposed core domain set may improve future trial design, evidence synthesis, and clinical relevance for patients, clinicians, and policy makers alike.

Reference:
Andersen CR, Fernie G, Presseau J, et al. International Position Paper on Outcome Selection After Aneurysmal Subarachnoid Hemorrhage. Stroke. 2026;57(2):560-567. doi:10.1161/STROKEAHA.125.053470