SUN-522 Use of U500 Along with Lispro Insulin in Pregnancy with Extreme Insulin Resistance

Abstract Disclosure: D.G. Varghese: None. N. Sherani: None. N. Kolta: None. R. Malek: None. H.B. Whitlatch: None. Background: Pregnancy can cause extreme insulin resistance. Successful diabetes management in pregnant patients with high insulin requirements is further challenged by the narrow glucose target required in pregnancy. U500 regular insulin has been used in patients requiring more than 200 Units (U) of insulin per day. However, it is often associated with late night hypoglycemia, necessitating frequent adjustment of U500 regular insulin dosing (twice or thrice daily) and/or regimens that combine U500 regular and rapid acting insulin. Case: 36-year-old female with history of type 2 diabetes mellitus requiring glargine 15 units and aspart 5 units three times a day (TID) prior to pregnancy was admitted to the hospital at 27 weeks (W) gestation for abdominal pain. She was receiving 80 units of glargine twice daily along with lispro 45 units TID and a correctional scale. Despite this, she was not meeting pregnancy time in range goals. As her inpatient requirement was more than 285 units of insulin a day, she was switched to U500 regular 95 units TID with improved glycemic control. Two weeks after hospital discharge, she returned to the emergency room (ER) for a self-reported low blood sugar of 47 mg/dL. She had a point of care glucose of 137 mg/dL in the ER, despite not taking any insulin for 48 hours. Hepatorenal and placental causes of hypoglycemia were ruled out. By 29W and 2 days (D) U500 regular was resumed, given progressively increasing insulin requirements. However, she continued to have post-prandial hyperglycemia as well as intermittent hypoglycemia. At 30W and 2D a 1-hour post-prandial lispro correctional scale was added to her TID U500 regular regimen. She received 1U of lispro for every 10 mg/dl over 110 mg/dl after breakfast and lunch and 1U of lispro for every 20 mg/dl over 140 mg/dl after dinner. This improved her post-prandial hyperglycemia and decreased the frequency of hypoglycemia. Her HbA1c at 31 weeks of gestation had improved to 7.8% from > 10% during the first trimester. Analysis of 10-day glucose values prior (85 readings) and after (77 readings) starting this regimen showed improvement in time between 95-140mg/dl (9% vs 33%) and > 180 mg/dl (60% vs 36%). She had an elective cesarean section at 34 weeks for pre-eclampsia with severe features and delivered a healthy baby weighing 2120 grams. Following delivery, her insulin requirements dropped dramatically, and she resumed her pre-pregnancy insulin dose of 30 units/day. Conclusion: Creative therapeutic treatment plans are often necessary to meet glycemic goals in pregnancy, particularly in patients who are very insulin resistant. Use of U500 regular along with rapid-acting insulin with or following meals is a viable option to improve post-prandial glucose excursions while avoiding hypoglycemic events in pregnant patients requiring more than 200 U of insulin daily Presentation: Sunday, July 13, 2025