Constructing the conditional association network and identifying central and bridge nodes in aneurysmal subarachnoid hemorrhage
摘要
Aneurysmal subarachnoid hemorrhage (aSAH) ranks among the most burdensome stroke subtypes in terms of years-of-life-lost. Existing models rely primarily on linear additive structures; explicit visualisation of factor-to-factor conditional dependencies remains limited. This study employed mixed graphical models (MGM) to restructure established clinical variables within a cross-sectional network framework, examining conditional independence structures among in-hospital clinical variables. This single-centre retrospective observational cohort included 374 aSAH patients admitted to a neurosurgical ward following definitive aneurysm treatment. The primary outcome was the discharge modified Rankin Scale (mRS), and a static network was constructed using data accrued over the entire hospitalization. Thirty-five routinely documented variables spanning demographics, severity scores (Glasgow Coma Scale, WFNS, modified Fisher), imaging characteristics, laboratory values, treatment modalities, in-hospital complications, temperature profiles and mRS underwent contemporaneous network analysis. MGM estimated pairwise conditional associations via LASSO-regularized Markov random fields (EBIC γ = 0.25, OR rule). Node strength centrality and bridge strength centrality quantified variable interconnectedness. Non-parametric bootstrap resampling (n = 1000) assessed edge weight stability. The cohort (mean age 53.9 ± 11.1 years; 60.7% female) exhibited dense interconnections among severity scores, temperature-derived indices, in-hospital complications, and therapeutic variables. Discharge modified Rankin Scale, Glasgow Coma Scale, mechanical ventilation and pneumonia occupied the highest ranks in both strength centrality and bridge strength centrality; these variables functioned as central and bridge nodes spanning the severity assessment, therapeutic intervention, and outcome evaluation communities. Conditioning on the multivariate conditional structure, the GCS-mRS relationship exhibited a pattern differing from the simple bivariate association. MGM restructured known aSAH clinical variables within a network topology, identifying Glasgow Coma Scale, mechanical ventilation and pneumonia as central and bridge nodes spanning multiple clinical domains. These central nodes represent candidates for future hypothesis-generating research, pending prospective validation.