Dysnatremia is the most common electrolyte disorder in hospitalized patients [1]. Dysnatremia is generally classified as hyponatremia (145mmol/L). Many studies showed that hypernatremia and hyponatremia are independently associated with an increased risk of poor clinical outcomes in hospitalized patients [1, 2], while serum sodium levels between 135 mmol/L and 145 mmol/L are previously treated as normal. Recent studies have focused on the correlation between hospital mortality and sodium fluctuations, even within sodium reference ranges [3].
