A Comparison of Insulin Doses for the Treatment of Hyperkalemia in Patients with Renal Insufficiency

STUDY OBJECTIVE: To compare the safety and efficacy of 5 units versus 10 units of insulin for the treatment of hyperkalemia in patients with renal insufficiency. DESIGN: Retrospective cohort study. SETTING: Large academic medical center emergency department. PATIENTS: Between March 1, 2008, and February 29, 2016, 675 patients met the inclusion criteria of age 18 years and older, serum potassium greater than 5 mEq/L, renal insufficiency, 5 units or 10 units of intravenous regular insulin administered in the emergency department, and blood glucose documented within 5 hours after insulin administration. Of these patients, 133 (19.7%) received 5 units of insulin and 542 (80.3%) received 10 units of insulin. MEASUREMENTS AND RESULTS: The primary outcome was incidence of hypoglycemia (blood glucose < 70 mg/dl). Secondary outcomes were incidence of severe hypoglycemia (blood glucose < 40 mg/dl) and change in serum potassium after insulin therapy. Hypoglycemia occurred in 26 of 133 patients receiving 5 units of insulin (19.5%) and in 155 of 542 patients receiving 10 units (28.6%) (difference = -9.1%, 95% confidence interval [CI] -16.8% to -1.3%). Severe hypoglycemia occurred in 4 of 133 patients (3.0%) and 37 of 542 patients (6.8%) receiving insulin 5 units and 10 units, respectively (difference = -3.8%, 95% CI -7.4% to 0%). Change in serum potassium was similar between groups (-1.0 ± 0.8 vs -1.0 ± 0.7 mEq/L, difference = 0, 95% CI -0.1 to 0.1). CONCLUSION: In patients with renal insufficiency and hyperkalemia, 5 units of insulin reduced serum potassium to the same extent as 10 units of insulin but with a lower rate of hypoglycemia. Further controlled studies are needed to confirm these findings.