Association between Plasma Osmolality and Case Fatality within 1 Year after Severe Acute Ischemic Stroke.

Abstract

PurposePlasma osmolality, a marker of dehydration, is associated with cardiovascular mortality. We aimed to investigate whether elevated plasma osmolality is associated with case fatality within 1 year after severe acute ischemic stroke.Materials and MethodsWe included severe ischemic stroke patients (defined as National Institutes of Health Stroke Scale ≥15 score) within 24 hours from symptom onset admitted to the Department of Neurology, West China Hospital between January 2017 and June 2019. Admission plasma osmolality was calculated using the equation 1.86*(sodium+potassium)+1.15*glucose+urea+14. Elevated plasma osmolality was defined as plasma osmolality >296 mOsm/kg, indicating a state of dehydration. Study outcomes included 3-month and 1-year case fatalities. Multivariable logistic regression was performed to determine independent associations between plasma osmolality and case fatalities at different time points.ResultsA total of 265 patients with severe acute ischemic stroke were included. The mean age was 71.2±13.1 years, with 51.3% being males. Among the included patients, case fatalities were recorded for 31.7% (84/265) at 3 months and 39.6% (105/265) at 1 year. Elevated plasma osmolality (dehydration) was associated with 3-month case fatality [odds ratio (OR) 1.98, 95% confidence interval (CI) 1.07–3.66, p=0.029], but not 1-year case fatality (OR 1.51, 95% CI 0.84–2.72, p=0.165), after full adjustment for confounding factors.ConclusionElevated plasma osmolality was independently associated with 3-month case fatality, but not 1-year case fatality, for severe acute ischemic stroke.