Safety of an Initial Insulin Bolus in the Treatment of Diabetic Ketoacidosis

Background Insulin is a mainstay of treatment in diabetic ketoacidosis (DKA) however controversy remains over the optimal dose and administration. An initial bolus dose of insulin prior to a continuous infusion is utilized despite a lack of data showing clinical benefit and potential for complications. Objective This study was designed to evaluate the safety and efficacy of an initial insulin bolus in the treatment of DKA. Methods A retrospective chart review of patients with DKA was conducted. Fifty-nine patients met inclusion for the bolus group and 108 in the no-bolus group. The primary outcome was a composite of interruption of insulin infusion, hypoglycemia (BG <70 mg/dL), or hypokalemia (K⁺ <3.4 mEq/L) occurring within eight hours of starting insulin. Secondary outcomes included time to discontinuation of insulin infusion, as well as time to discharge from the ICU and the hospital. Results Baseline characteristics were similar between groups. The majority of patients were classified as having mild DKA. The primary outcome occurred significantly more frequently in the bolus group (45.8% vs 25%, P = .003) which was primarily driven by incidence of hypokalemia. Time to anion gap closure (6:39 vs 9:00, P = .063) was shorter with a bolus, although not significantly so. This finding carried forward to non-significant differences in time to stopping insulin infusion as well as ICU and hospital discharge. Conclusion An insulin bolus prior to initiation of an insulin infusion was associated with significantly more adverse effects early in therapy without a corresponding benefit in time to resolution of DKA.