Is There Any Benefit to an Initial Insulin Bolus in Diabetic Ketoacidosis?

Diabetic ketoacidosis (DKA) is a common endocrine emergency encountered in the emergency department.  DKA associated mortality is relatively low in adults, but in children with type 1 diabetes, the elderly, and adults with concomitant illnesses have a mortality rate is > 5% [cite source=”pubmed”]19564476[/cite].  Guidelines for the management of hyperglycemic crisis in adults provide recommendations for intravenous fluid administration, correction of electrolyte abnormalities, insulin and bicarbonate therapy.  While the recommendations made in the American Diabetes Association (ADA) consensus statement are intended to be evidence based, there are two recommendations which have less than optimal supporting evidence which results in controversy in the emergency department: 1. Use of regular insulin boluses of 0.1 units/kg and 2. patients with a pH < 6.9 should receive sodium bicarbonate therapy.  Today we will attempt to answer the question, is there any benefit to an initial insulin bolus in DKA?

Is there a benefit to an initial insulin bolus in diabetic ketoacidosis?

Many prospective randomized trials have laid bare the use of low-dose insulin infusion leading to the successful recovery of patients with DKA.  However, the data supporting an initial insulin bolus prior to the initiation of insulin infusions is not nearly as robust.  The rationale for such a bolus is to overcome the relative insulin deficiency seen in DKA in order to suppress lypolysis and hepatic gluconeogenesis and limit further acidosis (more on that next time). However, insulin boluses may lead to harm including hypoglycemia, hypokalemia, and if glucose levels are too rapidly corrected, cerebral edema [1]. Since the publication of the ADA consensus statement, two investigations have attempted to answer the question of what affect insulin bolus has on patients with DKA [1] [2].

Take Home Points

• Insulin boluses at the start of an insulin infusion DO NOT:

1. 1. Decrease time to normalization of glucose, pH, or bicarbonate levels
   2. Affect the rate of change of glucose or anion gap
   3. Reduce ED or hospital length of stay

• Insulin boluses are associated with numerically higher, but statistically insignificant incidence of hypoglycemia requiring treatment with dextrose
• Clinical Bottom Line: There is no benefit to an insulin bolus before the start of an insulin infusion in DKA and may cause worsening hypoglycemia and hypokalemia.

References:

1. Goyal N et al. Utility of Initial Bolus Insulin in the Treatment of Diabetic Ketoacidosis. J Emerg Med 2010. PMID: 18514472
2. Kitabchi AE et al. Is a Priming Dose of Insulin Necessary in a Low-Dose Insulin Protocol for the Treatment of Diabetic Ketoacidosis? Diabetes Care 2008. PMID: 18694978