Association between hemispheric lateralization and 12-month stroke recurrence and mortality following ischemic...

Hemispheric lateralization in ischemic stroke may influence clinical presentation, treatment response, and long-term outcomes, yet its prognostic value beyond the acute care period remains underexplored. To examine whether the side of brain injury (left, right, or bilateral hemisphere) is associated with 12-month stroke recurrence and all-cause mortality in patients with ischemic stroke. We conducted a retrospective multicenter cohort study involving 672 adult patients with radiologically confirmed ischemic stroke from two tertiary hospitals in Saudi Arabia. Patients were categorized by hemisphere of injury. Clinical characteristics, comorbidities, complications, and interventions were recorded. The primary outcomes were 12-month stroke recurrence and all-cause mortality. Confounders were adjusted using directed acyclic graphs (DAGs) in multivariable logistic regression. Kaplan-Meier survival analysis was used to assess differences in mortality. Among 672 patients, 262 (38.9%) had left hemisphere strokes, 295 (43.8%) right, and 115 (17.1%) bilateral. Left-sided strokes had higher rates of aphasia (49.3%), impaired consciousness (45.1%), and right-sided motor deficits. After adjustment, left-hemispheric injury showed a non-significant trend toward higher 12-month stroke recurrence compared with right-sided strokes (OR = 1.60, 95% CI 0.95-2.70; p = 0.076). As for 12-month all-cause mortality, only age (OR = 1.04, 95% CI 1.03-1.06; p < 0.001), diabetes (OR = 1.68, 95% CI 1.01-2.85; p = 0.048), dyslipidemia (OR = 0.38, 95% CI 0.23-0.61; p < 0.001), and stroke subtype (type 2 vs. 1: OR = 0.32, 95% CI 0.17-0.59; p < 0.001) were significant predictors. Importantly, the hemispheric side was not independently associated with mortality. Left hemisphere ischemic strokes appear to be associated with more severe neurological deficits and lower long-term survival. These findings suggest the need for individualized post-stroke care and further prospective studies to clarify the prognostic role of stroke lateralization.