Nocturnal Hypoglycemia Associated with Bedtime Administration of Premixed Insulin Preparations in Hospitalized Patients.

Background: Patients with diabetes mellitus for whom premixed insulin preparations (PMIPs) are ordered in the hospital setting may be at risk of hypoglycemia if the PMIP is incorrectly administered at bedtime (instead of suppertime).

Objectives: The primary objective was to determine, retrospectively, the incidence of bedtime administration of PMIPs at a tertiary teaching hospital. The secondary objective was to investigate whether bedtime administration of PMIPs led to an increase in nocturnal hypoglycemia.

Methods: Inpatient PMIP orders for the period April 1, 2013, to March 31, 2017, were extracted from the pharmacy information system of the Queen Elizabeth II Health Sciences Centre, Halifax, Nova Scotia. Two hundred randomly selected inpatient admissions were audited, and instances of PMIP administration after 2000 (8 pm) were recorded. Data from an additional random sample of inpatient admissions, from January 1, 2016, to December 31, 2017, were reviewed to determine whether bedtime administration of PMIPs was associated with increased incidence of nocturnal hypoglycemia, relative to suppertime administration.

Results: In the randomly selected sample of 200 inpatient admissions, a PMIP was administered at bedtime at least once during 47 admissions (24%). In the additional sample of 123 inpatient admissions during which a PMIP had been administered, the mean nocturnal hypoglycemia rate was 4.15% for suppertime administration and 14.85% for bedtime administration (p = 0.13).

Conclusions: For a substantial proportion of patients, PMIPs were inappropriately ordered and administered at bedtime in this hospital setting and may have been associated with nocturnal hypoglycemic events. Recommendations to reduce this practice include ongoing education and a review of preprinted order sets.