Association between early platelet aggregation function and 30-day mortality in patients with cerebral hemorrhage: a retrospective neurocritical care cohort study

Background Cerebral hemorrhage has a high early mortality rate, and platelet function may be related to patient outcomes. However, the prognostic role of platelet aggregation function remains unclear. Objective To evaluate the associations of arachidonic acid (AA)-, adenosine diphosphate (ADP)-, and collagen (COL)-induced platelet aggregation with 30-day mortality in patients with cerebral hemorrhage, and to determine whether these indicators provided additional prognostic information beyond conventional clinical variables and disease severity scores. Methods This retrospective observational study enrolled adult patients with spontaneous intracerebral hemorrhage or traumatic cerebral hemorrhage admitted to the neurological intensive care unit (NICU) between September 2022 and April 2026. Platelet aggregation was assessed early after admission using light transmission aggregometry (LTA). The primary outcome was all-cause mortality within 30 days. Principal component analysis (PCA) was used to generate an integrated AA + ADP + COL PCA score. Candidate covariates were screened using least absolute shrinkage and selection operator (LASSO) regression, Boruta, and random forest methods, and the selected relevant variables were incorporated into multivariable logistic regression models. Supportive analyses examined discrimination, calibration, decision curve, incremental information beyond APACHE II, overlap-weighted estimates, and subgroup consistency. Results Among 335 included patients, 78 died within 30 days. In the fully adjusted models, higher platelet aggregation values were associated with a lower risk of 30-day mortality for AA (OR 0.978, 95% CI 0.964–0.992, p = 0.002), ADP (OR 0.960, 95% CI 0.942–0.978, p < 0.001), COL (OR 0.960, 95% CI 0.943–0.977, p < 0.001), and the AA + ADP + COL PCA score (OR 0.613, 95% CI 0.494–0.759, p < 0.001). In supplementary model assessment, the fully adjusted models demonstrated good discrimination, with areas under the receiver operating characteristic curves (AUCs) ranging from 0.839 to 0.857, acceptable bootstrap calibration, and positive clinical net benefit across a wide range of decision thresholds. In supportive analyses, adding platelet aggregation measures to an APACHE II-only model was associated with higher AUCs and favorable NRI/IDI results. Subgroup analyses showed generally consistent results across the pre-specified subgroups. The associations were directionally consistent in extended adjustment and overlap-weighted sensitivity analyses. Conclusion Reduced AA-, ADP-, and COL-induced platelet aggregation was associated with higher 30-day mortality after multivariable adjustment in patients with cerebral hemorrhage. Platelet aggregation testing may provide supportive prognostic information, but external validation and imaging-based confirmation were needed.