Heavy Alcohol and Aneurysm Rupture: Letter Flags Key Gaps in Meta-Analysis

A letter published in the Egyptian Journal of Neurosurgery raises methodological questions about a recent systematic review and meta-analysis examining the association between heavy alcohol consumption and intracranial aneurysm rupture. The letter, authored by Kaan Kırımlı, MD, of Trabzon Fatih State Hospital in Türkiye, congratulates the original authors for addressing a potentially modifiable risk factor for aneurysmal subarachnoid hemorrhage while outlining several considerations that may affect how the pooled findings should be interpreted.

The original meta-analysis, by Nahar and colleagues, combined 21 studies encompassing 680,233 participants and 5,243 confirmed cases of aneurysmal subarachnoid hemorrhage. It reported a pooled odds ratio of 2.25, with a 95 percent confidence interval of 1.71 to 2.97, indicating an association between heavy alcohol consumption and rupture of intracranial aneurysms. The letter acknowledges the value of synthesizing this large body of evidence but argues that several design and reporting issues deserve closer attention.

The first concern centers on how heavy drinking was defined. Because the meta-analysis took the highest consumption category reported by each individual study, the exposure thresholds differed substantially across the included research. The letter suggests this variability may introduce exposure misclassification and could partly explain the moderate heterogeneity observed in the pooled analysis, quantified as an I-squared value of 64.2 percent. The author notes that previous meta-analytic work has suggested dose-response analyses may add information about how alcohol consumption relates to subarachnoid hemorrhage risk.

A second point concerns the timing of alcohol exposure. Most of the included studies assessed habitual or long-term drinking, whereas the ACROSS study measured alcohol exposure shortly before the onset of subarachnoid hemorrhage using a case-crossover design. The letter argues that acute exposure and chronic consumption may represent different biological phenomena and should perhaps be analyzed separately in future work, rather than pooled together under a single exposure label.

The third consideration involves outcome definitions. Although the review focuses on aneurysmal rupture, some of the included studies evaluated broader hemorrhagic outcomes, including hemorrhagic stroke and subarachnoid hemorrhage generally. The letter contends that distinguishing confirmed aneurysmal rupture from other hemorrhagic cerebrovascular events would improve the clinical specificity of the pooled estimate, since not every hemorrhagic outcome in the combined studies necessarily reflects an aneurysm bursting.

Finally, the letter identifies a numerical discrepancy within the original article itself. The abstract and Results section report a pooled odds ratio of 2.25 with a confidence interval of 1.71 to 2.97, while the caption of Figure 4 reports 2.15 with a confidence interval of 1.75 to 2.64. The author suggests this may simply be a reporting or typographical error but states that clarification would be valuable for readers relying on the estimate.

The letter argues that the differing exposure definitions, temporal windows, and outcome criteria across the included studies warrant clarification to strengthen the interpretation and clinical applicability of the pooled findings.

The letter, formatted as correspondence to the editor rather than original research, was published on 12 October 2026 in Volume 41 of the journal as article number 172, and it references an original article published on 19 August 2026.

The letter does not dispute the existence of the association but asks for greater precision in defining heavy drinking, separating acute from chronic exposure, restricting outcomes to confirmed aneurysmal rupture, and reconciling the differing pooled estimates reported within the original publication.

Subject of Research: Methodological critique of a meta-analysis on heavy alcohol consumption and intracranial aneurysm rupture

Article Title: Methodological considerations regarding heavy alcohol consumption and intracranial aneurysm rupture

Article References: Kırımlı, K. (2026). Methodological considerations regarding heavy alcohol consumption and intracranial aneurysm rupture. Egyptian Journal of Neurosurgery, 41(1), Article 172. https://doi.org/10.1186/s41984-026-00680-1

Image Credits: AI Generated

DOI: 10.1186/s41984-026-00680-1

Keywords: intracranial aneurysm, subarachnoid hemorrhage, heavy alcohol consumption, meta-analysis, methodology, heterogeneity, exposure misclassification, case-crossover, odds ratio, Egyptian Journal of Neurosurgery, Methodological, considerations