Temporal and Geographic Variation in Outcomes After Poor-Grade Aneurysmal Subarachnoid Hemorrhage: A Systematic Review and Meta-analysis
Abstract
Background: Poor-grade aneurysmal subarachnoid hemorrhage (aSAH) remains associated with high mortality and severe disability, yet contemporary outcomes may differ substantially from historical estimates. We performed a systematic review and meta-analysis to evaluate long-term outcomes after poor-grade aSAH and assess temporal, geographic, and treatment-related factors associated with prognosis.
Methods: PubMed/MEDLINE, Embase, Cochrane Central, Scopus, and Google Scholar were searched from inception through March 2026. Studies enrolling consecutive adults with poor-grade aSAH (World Federation of Neurosurgical Societies grades IV–V, Hunt–Hess grades IV–V, or equivalent) reporting mortality and/or functional outcomes at ≥3 months were included. To minimize survivorship bias, studies excluding untreated patients or patients dying before aneurysm treatment were excluded. Random-effects meta-analyses of proportions were performed using generalized linear mixed models. Prespecified subgroup analyses and exploratory meta-regression analyses evaluated temporal, geographic, and treatment-related factors associated with outcomes.
Results: Forty-two studies including 7,726 patients from 16 countries across 4 continents were included. The pooled favorable functional outcome rate was 27.2% (95% CI, 23.9%–30.8%), whereas pooled overall mortality was 53.3% (95% CI, 49.0%–57.5%). Pre- and post-treatment mortality were 25.9% and 33.9%, respectively. Aneurysm treatment rate was 72.0% (95%…
How strong is the evidence?
Evidence Hub reads this as a meta-analysis, done in people. Its evidence level is 1 of 5 (Highest · pooled evidence). Pooled evidence from several studies sits at the top of the evidence pyramid. Reported size: 7,726 participants or records.
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