Inverse distribution of serum sodium and potassium in uncontrolled inpatients with diabetes mellitus

It has been reported that there is an inverse relationship between serum sodium (Na) and potassium (K) levels in patients with diabetic coma. The present study was undertaken to determine whether such an inverse relation depends upon plasma glucose levels in diabetic patients for their glycemic control. We examined two hundred and fifty-two patients with diabetes mellitus admitted to our hospital during the one-year period to control their plasma glucose levels, except for those having nephropathy or liver dysfunction. Serum Na and K, plasma glucose, and serum and urinary C-peptide levels were determined. There was a negative correlation between serum Na levels and fasting plasma glucose (FPG), and, conversely, a positive correlation between serum K levels and FPG. The changes were more evident in the patients with insulin-dependent diabetes mellitus than those with non-insulin-dependent diabetes mellitus. There was an inverse relation between serum Na and K levels and it was profoundly dependent upon plasma glucose levels in all the diabetic patients before tight control of their glycemic levels. The disorder may be based on the movement of electrolytes between intra- and extracellular spaces, dependent on the impaired insulin action as well as hyperosmolality.