Shorter is not always better: Stroke unit length of stay and outcomes after acute ischemic stroke

BACKGROUND AND OBJECTIVE: Stroke Unit (SU) care is a cornerstone of acute ischemic stroke (AIS) management, yet typically conceptualized as a binary exposure. The prognostic impact of SU length of stay variability remains unclear. We investigated the association between SU length of stay and outcomes in AIS patients, exploring whether its determinants carry implications for stroke care organization. METHODS: Retrospective analysis of a prospective single-center register of consecutive AIS patients admitted to a dedicated SU between January 2023 and December 2024. Analyses were restricted to patients surviving beyond 72 h (landmark design). Exposure was categorized as prolonged (>3 days) versus shorter (≤3 days) SU stay. IPW was applied to adjust for baseline differences. Primary outcome was 90-day all-cause mortality; secondary outcomes included in-hospital mortality and 90-day functional outcome. RESULTS: The landmark cohort included 909 patients; 291 (32.0%) had a prolonged SU stay. Among patients with a shorter stay, 66.8% were discharged early due to bed pressure rather than clinical readiness. Prolonged SU stay was associated with lower 90-day mortality (IPW-adjusted OR 0.50, 95% CI 0.37-0.68) and a favorable shift in functional outcome (IPW-adjusted common OR 0.78, 95% CI 0.66-0.92). Patients discharged early due to bed pressure showed higher mortality (IPW-adjusted OR 1.71, 95% CI 1.01-2.97) and worse functional outcomes (IPW-adjusted common OR 1.34, 95% CI 1.02-1.76). CONCLUSIONS: Prolonged SU stay was associated with lower mortality and more favorable functional outcomes. Premature discharge driven by bed pressure carried a measurable clinical cost, supporting a patient-centered approach beyond simple access metrics.