Insulin therapy for diabetic ketoacidosis. Bolus insulin injection versus continuous insulin infusion

Despite widespread acceptance of continuous insulin infusion (CII) over bolus insulin injection (BII) for treatment of diabetic ketoacidosis (DKA), there are no population-based studies demonstrating whether CII has resulted in lower morbidity and mortality.

We addressed this issue using a provider-linked database and retrospectively reviewing the complete medical records of all incidence cases of diabetes among Rochester, Minnesota, residents from 1950 to 1989 with a discharge diagnosis of DKA. This population-based study describes the consequences of the widespread change in treatment modality outside the confines of a controlled clinical trial.

Among the diabetes incident cohort, there were 59 subjects with confirmed first episodes of DKA during 1950-1992; 29 of 30 subjects treated with BII occurred before 1970. All 29 CII cases occurred between 1976 and 1992. Sex, etiology, diabetes duration, and age at DKA were similar for the two groups. The proportion of obese individuals (BII = 2/28, CII = 8/21; P = 0.01) differed between groups. The CII group exhibited higher glucose values (BII = 24.9 +/- 8.5 mmol/l, CII = 37.1 +/- 15.1 mmol/l; P = 0.002) and lower bicarbonate values (BII = 7.7 +/- 3.0 nmol/l, CII = 6.2 +/- 2.9 nmol/l; P = 0.04) upon admission. The mean quantity of insulin administered was higher in the BII group than in the CII group (179 +/- 140 and 99 +/- 70 U, P < 0.006). The outcome of hypoglycemia occurred more frequently in the BII group than in the CII group (BII = 8/30, CII = 1/29; P = 0.03). The proportion with hypokalemia, neurological deficit, myocardial arrhythmia, or mortality did not differ significantly between groups.

Our findings suggest the introduction of CII was accompanied by a decreased incidence of hypoglycemia.