After acute stroke, patients are at risk of development of dehydration which is usually hyperosmolar. This abnormal physiological environment may influence early neurological deterioration and unfavorable outcome after acute stroke. We evaluated the association of raised plasma osmolarity with acute stroke outcome at 28 days. We enrolled two independent groups of acute stroke patients. Fifty patients of acute stroke with high plasma osmlarity (plasma osmolarity ≥296 mmol/L) were included in the hyperosmolar group and another 50 patients with normal osmolarity  included in the normal osmolar group (plasma osmolarity ≥280 to <296 mmol/L). We applied quota method of sampling to enroll the samples. Plasma osmolarity was calculated on admissions who were admitted within 24 hours after acute stroke. Chi square test and logistic regression test were done to evaluate the association of osmolarity and outcome (death and functional status). Functional status was measured with Birthel Index score scale. Thirty four deaths were observed during the study period. Among the death cases, 21 acute stroke patients were hyperosmolar (mean osmolarity 303.43 with SD±6.60) on admission and 13 acute stroke patients were normalosmolar on admission (mean osmolarity 289.13 with SD±5.76). Statistical analysis showed admission hyperosmolarity was not associated with fatal acute stroke outcome crude OR 2.06 (p value 0.09) and adjusted OR 0.923(95%CI 0.338 to 2.523,p value0.87).  Among the 66 survivor, 21 were towards dependent and 8 patients were towards independent after 28 days in hyperosmolar group. Logistic regression analysis showed hyperosmolarity was not associated with poor functional outcome of acute stroke than that of normal osmolarity group with adjusted OR 0.250 (95% CI 0.054 to 1.164). So raised plasma osmolarity was not associated with acute stroke mortality and poor functional outcome.

Keywords: Hyperosmolarity, Birthel Index Score