Relationship between Serum Sodium level and Impairment and Disability in Stroke Patients

Hyponatremia is associated with adverse outcomes and increased mortality in acute stroke patients. However, the role of hyponatremia as a negative prognostic indicator has been controversial. This study was conducted to determine the relationship between serum sodium level and impairment and disability in stroke patients in Babol, northern Iran.

This cross-sectional study was conducted in 6 months on 125 stroke patients admitted to Ayatollah Rouhani Hospital in Babol. The National Institutes of Health Stroke Scale and the Modified Rankin Scale were used to determine the impairment and disability caused by stroke. Venous blood was collected to determine the serum concentrations of sodium. The normal ranges were defined as 135-145 mEq/L.

Of 125 stroke patients, 108 cases (86.4%) were ischemic stroke. Eighty-two cases (65.5%) had hyponatremia. The type of stroke showed statistically significant difference with hyponatremia in 14 hemorrhagic stroke cases (17%) versus 68 ischemic stroke cases (83%) (p=0.01). Furthermore, the difference in gender showed statistically significant difference with hyponatremia in 49 women (59%), and 33 men (41%) (p=0.02). In hyponatremic patients, the severity of impairment at admission (p=0.01) and disability at discharge time (p=0.02) was higher than patients with normal sodium serum level. In patients with a history of smoking, 9 cases (21%) had normal sodium level while 33 cases (79%) had hyponatremia (p=0.03).

The results of the present study showed that the severity of impairment and disability at the time of discharge in stroke patients is related to serum sodium level. Therefore, paying attention and correcting serum sodium level should be considered more in acute stroke patients.