Hydration Status and Clinical Outcomes in Ischemic Stroke

Hydration status has emerged as a pivotal factor influencing the trajectory of recovery and long-term prognosis after ischaemic stroke. Dehydration at the time of cerebral infarction exacerbates blood rheology, promotes hypoperfusion and elevates the risk of early neurological deterioration. Conversely, adequate hydration supports cerebral perfusion, mitigates infarct expansion and can improve functional outcome. Key markers of hydration—such as the blood urea nitrogen to creatinine ratio (BUN/Cr), urine specific gravity and whole blood viscosity—have been investigated as predictors of neurological decline and disability. Patient characteristics including age, sex and baseline stroke severity further modulate the impact of hydration status. Globally, simple, low-cost interventions to ensure early and targeted rehydration could transform acute stroke care, particularly in resource-limited settings, by reducing mortality and improving independence at three months and beyond.

Research from Nature Portfolio

Recent studies have explored the role of blood viscosity in patients with symptomatic middle cerebral artery atherosclerosis. Researchers compared low- and high-shear viscosity across in situ thrombo-occlusion, artery-to-artery embolism and local branch occlusion. Blood viscosity was highest in in situ thrombo-occlusion and correlated strongly with early neurological deterioration. Importantly, low-shear viscosity emerged as an independent predictor of deterioration across all stroke mechanisms within the first week. These insights emphasise the mechanistic link between altered haemorheology and clinical decline, suggesting that therapeutic modulation of viscosity could become a novel target in stroke management.

Hydration Status and Clinical Outcomes in Ischemic Stroke publication trend

The graph below shows the total number of articles in hydration status and clinical outcomes in ischemic stroke across all publications each year (not limited to Nature Index journals).

Technical terms

Blood viscosity: A measure of the internal resistance of blood to flow, influenced by haematocrit, plasma proteins and shear rate.

BUN/Cr ratio: The ratio of blood urea nitrogen to creatinine, a surrogate marker for hydration status and renal perfusion.

Early neurological deterioration (END): A worsening of neurological function, often defined as an increase of four or more points on the NIH Stroke Scale within days of onset.

Urine specific gravity (USG): A laboratory measure of urine concentration, reflecting body fluid balance and renal concentrating ability.

Modified Rankin Scale (mRS): A seven-point scale (0–6) assessing the degree of disability or dependence in daily activities after stroke.

References

1. Blood viscosity associated with stroke mechanism and early neurological deterioration in middle cerebral artery atherosclerosis. Scientific Reports (2023).
2. Impact of early and rapid hydration for patients with ischemic stroke within 24 hours of onset. Heliyon (2025).
3. Contribution of dehydration to END in acute ischemic stroke not mediated via coagulation activation. Brain and Behavior (2019).