Association of Admission Albumin and White Blood Cell Count with Stroke Severity and Hospital Length of Stay in Acute Ischemic Stroke

Background Inflammation and nutritional status play crucial roles in the pathophysiology and prognosis of acute ischemic stroke (AIS). However, the independent associations of admission white blood cell (WBC) count and serum albumin with both stroke severity and hospital length of stay (LOS) remain insufficiently characterized. This study aimed to investigate these relationships in a cohort of Chinese patients with AIS. Methods We retrospectively analyzed 434 AIS patients admitted within 24 hours of symptom onset. Patients were stratified into tertiles based on admission albumin and WBC levels. Multivariable linear regression models were used to assess associations with admission NIHSS score and log-transformed LOS, with progressive adjustment for confounders. Generalized additive models (GAM) were applied to explore nonlinear relationships, and subgroup analyses were performed to examine consistency across populations. Results Higher WBC count was independently associated with greater stroke severity. In the fully adjusted model, patients in the highest WBC tertile had significantly higher admission NIHSS scores (β = 2.03, 95% CI 0.90–3.16, P < 0.001). Atrial fibrillation was the strongest predictor of stroke severity (β = 5.45, 95% CI 3.92–6.98, P < 0.001). For albumin, no significant association was found with admission NIHSS (P for trend = 0.83). However, lower albumin levels were associated with prolonged hospital stay. In the fully adjusted model, patients in the highest albumin tertile had shorter LOS (β = − 0.143, 95% CI − 0.298 to 0.012, P = 0.071), with a borderline significant trend (P = 0.071). GAM analysis confirmed a significant near-linear inverse relationship between albumin and log-LOS (P = 0.0012). Subgroup analyses showed consistent effects across sex, age, diabetes, and atrial fibrillation groups, with notable effect modification by sex and age. Conclusions Elevated admission WBC count is independently associated with increased stroke severity, while lower serum albumin levels are independently associated with prolonged hospitalization in AIS patients. These readily available biomarkers may serve as simple and cost-effective tools for early risk stratification and may guide nutritional and anti-inflammatory interventions in acute stroke care. Trial registration Not applicable. This study was a retrospective cohort study and did not involve a clinical trial.