Association of Hyponatremia With Severity and Outcome in Acute Hemorrhagic Stroke: An Observational Study From a Neurology Tertiary Unit

Background: Hyponatremia is the most common electrolyte disturbance encountered in patients with acute hemorrhagic stroke and has been associated with adverse neurological outcomes in international literature. However, region-specific evidence from tertiary neurology units in Pakistan remains scarce. This study aimed to evaluate the frequency of hyponatremia, its association with stroke severity, and its impact on clinical outcomes in patients admitted with acute hemorrhagic stroke to a tertiary neurology unit in Pakistan. Methods: This prospective longitudinal observational study was conducted in the Department of Neurology, Pak Emirates Military Hospital, Rawalpindi. A total of 200 patients with confirmed acute hemorrhagic stroke were enrolled using consecutive non-probability sampling over four months. Hyponatremia was defined as serum sodium below 135 mmol/L measured within 24 hours of admission. Stroke severity was assessed by the National Institutes of Health Stroke Scale (NIHSS) at admission and discharge. Clinical outcomes were assessed using the modified Rankin Scale (mRS) at discharge and 90 days post-discharge. Multivariable logistic regression identified independent predictors of unfavorable outcome. Results: Hyponatremia was identified in 84 patients (42.0%). SIADH was the predominant etiology (69.0%). Hyponatremic patients demonstrated significantly higher NIHSS scores at admission (16.8 ± 4.2 vs 11.3 ± 3.9; p<0.001) and discharge (14.1 ± 4.8 vs 8.6 ± 3.7; p<0.001). In-hospital mortality was significantly higher in the hyponatremic group (26.2% vs 8.6%; p<0.001). Unfavorable functional outcomes at 90 days were present in 72.6% of hyponatremic versus 26.7% of normonatremic patients (p<0.001). On multivariable logistic regression, hyponatremia was the strongest independent predictor of unfavorable outcome (OR 3.4, 95% CI 1.9–6.1; p<0.001). Conclusion: Hyponatremia is frequent and independently associated with greater stroke severity, higher in-hospital mortality, and worse functional outcomes in acute hemorrhagic stroke. Serum sodium should be incorporated into routine risk stratification protocols, particularly in resource-limited settings.