U-500 regular insulin use in hospitalized patients

U-500 is a potent insulin used in patients with severe insulin resistance. This study aimed to describe the inpatient insulin requirements, insulin regimens, and glycemic control of hospitalized patients using U-500.

A retrospective chart review of adult patients using U-500 insulin at home who were admitted to Cleveland Clinic hospitals between 2001 and 2011 was performed. Two groups were compared: those who were given U-500 while hospitalized (Group A) and those who were switched to a different insulin regimen (Group B). The percentages of hypoglycemia days and hyperglycemia days were calculated as the number of days with the respective event divided by the length of stay (LOS) in days for each patient.

There were 61 patients, 59% of which were male, with a median body mass index (BMI) 38.4, age 60.8 years, hemoglobin A1c 8.9% or 74 mmol/mol, and LOS 5.0 days. The majority (66%) remained on a U-500-based insulin regimen, while the rest were switched to a combination of long-, intermediate-, short- and/or fast-acting insulin. The endocrinology service was consulted for 61% of patients. Glucose levels were not significantly different between the 2 groups. Group B was given less insulin in the hospital compared to their home regimen. Group A had more frequent hypoglycemia days (mean ± SD: 15.3 ± 21.3 vs. 2.8 ± 6.4%) and more frequent severe hyperglycemia days (16.8 ± 21.8 % vs. 6.3 ± 9.8%) than Group B.

This study suggests that there is a subset of patients on U-500 at home who might be managed on conventional insulin in the hospital. Patients who remain on U-500 in the hospital tend to continue with a high insulin dose requirement, which might predispose them to more frequent hypoglycemia.