Temporal changes in clinical practice and mortality in aneurysmal subarachnoid hemorrhage following the 2012 AHA/ASA guidelines: a retrospective cohort study using the MIMIC database.

BACKGROUND/

objectiveAneurysmal subarachnoid hemorrhage (aSAH) carries high morbidity and mortality. The 2012 AHA/ASA aSAH management guidelines introduced recommendations for standardized monitoring, vasospasm prevention with nimodipine, blood pressure control, early aneurysm repair, and selective use of antiseizure medication (ASM) in the immediate post-hemorrhagic period. The overall impact of the guideline period on patient outcomes in real-world ICU practice remains incompletely characterized.

methodsWe conducted a retrospective cohort study of adults admitted to the ICU with aSAH between 2001 and 2019 using MIMIC-III and MIMIC-IV, linked de-identified electronic health record databases from a single academic center. Patients were grouped into Period 1 (pre-guideline, 2001-2011) and Period 2 (post-guideline, 2012-2019). Outcomes included mortality at 1, 6, and 12 months; ASM use; seizure occurrence; and ICU/hospital length of stay (LOS). Logistic regression was used for binary outcomes and quantile regression for median LOS, with unadjusted, demographic-adjusted, and fully saturated models. Sensitivity analyses stratified by Glasgow Coma Scale (GCS), Hunt and Hess (HH), and modified Fisher grade (mFG) were performed.

resultsA total of 516 patients (279 pre-guideline; 237 post-guideline) were included. ASM use increased from 63.3% to 92.0% post-guideline. In fully saturated models, mortality was significantly lower in the post-guideline cohort at 1 month (OR 0.17, 95% CI 0.04-0.67), 6 months (OR 0.17, 95% CI 0.05-0.64), and 1 year (OR 0.16, 95% CI 0.04-0.61). Seizure occurrence was numerically higher in Period 2 in unadjusted analyses but this difference was not significant in the saturated model. LOS effects were mixed. The largest mortality reductions occurred in patients with low GCS, high HH, and high mFG scores.

conclusionsIn the period following publication of the 2012 AHA/ASA aSAH guidelines, ICU mortality decreased significantly and ASM use increased substantially at a single academic center. These temporal associations are consistent with guideline-driven practice change, but cannot be attributed exclusively to guideline implementation given the observational pre-post design and the many concurrent advances in neurocritical care. The mortality reduction was most pronounced in patients with high-severity aSAH. These findings highlight the value of systematic outcomes monitoring following major guideline updates and identify high-severity aSAH as a priority population for future prospective evaluation.