Glycemic Outcomes of Hospitalized Patients on Ambulatory Humulin-R U-500 Insulin

Abstract

Objective: Managing hospitalized patients on ambulatory U-500 insulin is challenging because of limited guidance on how to safely adjust insulin doses during admission. We sought to evaluate glycemic outcomes in relation to inpatient insulin doses in patients receiving U-500 prior to hospitalization.

Methods: Retrospective study of hospitalized patients on ambulatory U-500 seen consecutively from January 2015 to December 2019. Primary outcomes were inpatient hypoglycemia, hyperglycemia, and normoglycemia at different insulin dosages expressed as weight-based (unit/kg/d) inpatient total daily dose (TDD) and ratio of inpatient to outpatient TDD.

Results: We identified 66 admissions of 46 unique patients. The median (interquartile range) body mass index was 41.0 kg/m² (35.1, 46.8), home TDD 212 units (120, 300), and home insulin dose 1.6 units/kg/d (1.1, 2.2). The median (interquartile range) inpatient insulin dose was 0.7 unit/kg/d (0.3, 1.0) and the ratio of inpatient to outpatient TDD was 0.4 (0.2, 0.8). Hyperglycemia persisted throughout the hospitalization. For the outcomes of hyperglycemia and normoglycemia, we found no association between increased levels of insulin dosages. For the outcome of hypoglycemia, significantly higher odds were observed when non-fasting patients received an inpatient TDD that was either > 40% of their home TDD or > 0.6 unit/kg/d of insulin.

Conclusion: Patients on ambulatory U-500 have significant hyperglycemia during admission. Inpatient insulin doses of 40% of home TDD or ≤ 0.6 unit/kg were not associated with increased hypoglycemia risk. Further prospective studies are needed to determine effective doses in these high-risk patients.

Keywords: concentrated insulin; diabetes mellitus; glycemic control; hospitalization; humulin-R U-500.