Treatment with Mannitol is Associated with Increased Risk for In-Hospital Mortality in Patients with Acute Ischemic Stroke and Cerebral Edema

Background Current guidelines state that osmotic therapy is reasonable in patients with clinical deterioration from cerebral infarction-related cerebral edema. However, there are limited data on the safety and efficacy of this therapy. We aimed to evaluate the effect of mannitol on the outcome of ischemic stroke-related cerebral edema. Methods and Results We prospectively studied 922 consecutive patients admitted with acute ischemic stroke. Patients who showed space-occupying brain edema with tissue shifts compressing the midline structures received mannitol. The outcome was assessed with dependency rates at discharge (modified Rankin Scale grade 2-5) and in-hospital mortality. Rates of dependency were higher in patients treated with mannitol (n=86) than in those who were not (97.7 and 58.5%, respectively; p<0.001). Independent predictors of dependency were age, history of ischemic stroke and National Institutes of Health Stroke Scale (NIHSS) score at admission. Rates of mortality were higher in patients treated with mannitol than in those who were not (46.5 and 5.6%, respectively; p<0.001). Independent predictors of in-hospital mortality were diastolic blood pressure [relative risk (RR) 1.05, 95% confidence interval (CI) 1.02-1.08, p<0.001], NIHSS score at admission (RR 1.19, 95% CI 1.14-1.23, p<0.001) and treatment with mannitol (RR 3.45, 95% CI 1.55-7.69, p<0.005). Conclusions Administration of mannitol to patients with ischemic stroke-related cerebral edema does not appear to affect the functional outcome and might increase mortality, independently of stroke severity.