Introduction:
Hyponatremia is examined as a prognostic factor after first-time ischemic cerebrovascular incident (CVA, ischemic stroke).

Material and methods:
677 patients were analyzed after first-time ischemic stroke and divided into two groups according to sodium concentration: ≤ 135 mmol/L and > 135 mmol/L.

Results:
For patients with sodium levels ≤ 135 mmol/L, the median National Institutes of Health Stroke Scale (NIHSS) score was 5 points, the median Modified Rankin Scale (mRS) was 4 points, and the mortality within 1 month of ischemic stroke was 10.5%. Patients with sodium levels > 135 mmol/L: NIHSS 3 points, mRS 2 points and mortality 1 month after ischemic stroke 3.4%. Mortality within 1 month of ischemic stroke in hyponatremic patients: women 16.4%, men 3.5% (p = 0.0194). Greater disability was seen in eunatremic women as assessed by increased mRS scores (p = 0.005).

Conclusions:
Hyponatremia is associated with a worsened heath status in patients in the acute and sub-acute phase after first-time ischemic stroke and is associated with increased mortality within 1 month after the stroke. Women with hyponatremia were characterized by greater mortality within one month after their first-ever ischemic stroke. In women with normal serum sodium at the time of stroke, a higher degree of disability was observed as assessed by increased mRS scores compared to men.