Hyperkalemia and hyperglycemic increments in plasma potassium in diabetes mellitus.

The frequency of persistent or intermittent hyperkalemia in patients with diabetes is unknown. In 405 predominantly insulin-treated patients, major hyperkalemia was not common (< 5.0 mEq/L in 2.5%). In ten insulin-treated patients sampled hourly from 8 AM through 8 PM, major intermittent hyperkalemia was not detected (< 4.8 mEq/L in all samples). However, mean plasma potassium values paralleled mean glucose values; these variables were significantly correlated in seven of ten patients. In contrast, there were no relationships between plasma potassium and plasma free insulin, glucagon, epinephrine, or norepinephrine values. We conclude that (1) hyperkalemia--fasting or intermittent--does not occur commonly in patients with diabetes, and (2) hyperglycemia, but not insulin or epinephrine lack or glucagon excess, appears to be a direct determinant of plasma potassium but is not a sufficiently potent determinant to commonly produce clinically important hyperkalemia in insulin-treated diabetic patients.