Patients Using U-500 Insulin Require Significantly Reduced Insulin Doses while in the Hospital

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 839-872-Diabetes & Obesity Management
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-863
Kristen Gilbert*1, Umal Azmat2 and James Paul Walsh3
1Indiana University, Indianapolis, IN, 2Indiana University, 3IN Univ, Indianapolis, IN
Background: Patients admitted to a hospital often require adjustment of their insulin doses due to changes in diet, activity, and the stress of illness.  We performed a retrospective cohort study of hospitalized patients who were all taking U-500 as outpatients to ascertain their inpatient insulin requirements.

Methods: This study was performed in a large, tertiary-care VA Medical Center.  We identified 44 admissions of 35 patients over a 10 year period with active outpatient orders for U-500 insulin and reviewed their medical records.  All the patients were consuming meals and were managed with subcutaneous insulin while in the hospital.  Admissions less than one day in duration were not included.

Results:  Patient demographics (mean ± SD) included age 57.4 ± 6.9 years, weight 138 ± 35 kg, BMI 44.7 ± 10.0, and hemoglobin A1c 8.7 ± 1.5 %.  All patients had type 2 diabetes.  Average daily outpatient insulin use was 2.8 ± 0.8 units/kg/day.  The mean length of stay was 3.7 ± 2.7 days.  Primary admission diagnoses were cardiovascular in 22, infectious in 9, gastrointestinal in 5, pulmonary in 4, and other in 4.  U-500 was used in 24 admissions and U-100 in 20.  There were no significant differences between U-500 and U-100 groups in age, hemoglobin A1c, weight, BMI, eGFR, Charlson comorbidity index, length of stay, admission diagnosis category, or 90-day mortality. 

Excluding the first hospital day, a glucose <80 mg/dL occurred in 14 patients treated in the hospital with U-500 insulin, but only 2 treated with U-100 (p=0.001).  The total daily insulin dose and a non-carbohydrate controlled diet were each also associated with low glucose.  However, inpatient U-500 insulin still predicted low blood glucose in a logistic regression model after adjustment for these two factors (adjusted odds ratio 9.4, p=0.025).  For all 16 patients experiencing a glucose < 80 mg/dl, the mean total daily insulin on the hospital day with the lowest glucose was 77.3 ± 26.7% of the home insulin dose.  

At least one full day of good glycemic control, defined as an average glucose ≤ 200 mg/dL and no glucoses ≤ 80 mg/dL, occurred during 37 of the 44 admissions.  For these 37 admissions, the mean glucose on the day with best control was not significantly different between The U-500 and U-100 groups (145 ± 31 vs.  141 ± 23 mg/dL, p=0.656).  The mean insulin dose on these days was 1.9 ± 0.9 units/kg/day in patients treated with U-500 and 1.1 ± 0.8 units/kg/day in those treated with U-100 (70.8% vs. 44.6% of home dose, p = 0.013).

Conclusions: Patients using U-500 insulin require substantial dose reductions while in the hospital to avoid iatrogenic hypoglycemia.  Insulin doses required to manage inpatient glycemia in most, if not all, of these patients can be safely and effectively given as U-100 insulin.

Nothing to Disclose: KG, UA, JPW

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