Serial glucose-to-potassium ratio burden predicts long-term outcomes after aneurysmal subarachnoid hemorrhage

Background The glucose-to-potassium ratio (GPR) is a prognostic biomarker after aneurysmal subarachnoid hemorrhage (aSAH), but prior studies have focused mainly on admission values. Whether cumulative GPR burden or longitudinal trajectory improves prognostic assessment remains unknown. Methods We performed a retrospective single-center cohort study of 309 adults with aSAH who had admission GPR, ≥2 serial GPR measurements, and documented outcomes. Exposure metrics included admission GPR, mean GPR, peak GPR, GPR-time area under the curve (AUC), and trajectory slope. Outcomes included 1-year mortality, poor functional outcome at follow-up (modified Rankin Scale [mRS] 3–6), and radiographic vasospasm. Multivariable models adjusted for age, sex, Hunt–Hess grade, and modified Fisher grade. Sensitivity analyses included landmark slope analyses, diabetes stratification, and exclusion of early deaths. Results Among 309 patients (median age 56 years; 64.1% female), 222 had 1-year vital status, including 33 deaths (14.9%). In adjusted analyses (n=209; 32 deaths), mean GPR (adjusted odds ratio [aOR] 2.47, 95% CI 1.58–3.86; P<0.001) and GPR-time AUC (aOR 2.62, 95% CI 1.66–4.12; P<0.001) independently predicted 1-year mortality, whereas admission GPR did not (aOR 1.25, 95% CI 0.80–1.93; P=0.326). Trajectory slope showed a weak, non-robust association. Mean GPR also predicted poor functional outcome (aOR 1.47, 95% CI 1.01–2.14), while no GPR metric predicted radiographic vasospasm. Mean GPR demonstrated strong mortality discrimination (ROC AUC 0.877). Conclusions Serial GPR measurements provide prognostic information primarily through cumulative metabolic burden rather than temporal trajectory. Mean GPR and GPR-time AUC may improve longitudinal risk stratification after aSAH. External validation is warranted.