8475 Automated Insulin Delivery System with Concentrated Regular U500 Insulin in Cushing Syndrome

Abstract Disclosure: F. Erenler: None. J. Aurora: None. Background: Concentrated regular U-500 (U-500R) insulin is commonly used in patients with T2DM, who are highly insulin-resistant, requiring more than 200 units of insulin per day. Utilizing U-500R reduces the number of daily injections, decreases injection volume, and improves cost effectiveness. There has been a case report with U-500R in an automated insulin delivery (AID) system with successful results (1). To our knowledge there is no data on AID system use in Cushing patients with T2DM using U-500R. We present a case of a patient with Cushing Syndrome (CS) with poor BG control using >250 units/day of SC U-500R with improved BG control after switching to Omnipod 5 AID system. Clinical Case: A 57 y.o. male initially presented with hypogonadotropic hypogonadism and subsequently diagnosed with ACTH-dependent CS, which is complicated by obesity, uncontrolled T2DM, lower extremity wounds, and DVTs. He was diagnosed with CS with multiple abnormal 1 mg dexamethasone suppression tests (DST) (max AM cortisol 5.9 mcg/dL; RR <1.8 mcg/dL, dexamethasone level 300), elevated urine free cortisol (UFC) (max UFC/Cr 77.6 mcg/mg/L; RR: 5-64 mcg/24-hr) and elevated salivary cortisol (max cortisol 0.2 mcg/dL; RR: <0.09 mcg/dL). He had suppressed cortisol with 8 mg DST. An MRI sella showed left-sided hypoechoic 0.9 cm mass. Desmopressin (DDAVP) stimulation test and Ga-68 DOTATATE-PET scan were negative. As a result of his abnormal MRI sella and elevated cortisol, he underwent transsphenoidal surgery of the left pituitary. Pathology was non-diagnostic for a pituitary adenoma. Post-op 24-hr UFC and 1 mg DST levels remained high. DDAVP stimulation test and Ga-68 DOTATATE-PET were repeated post-op and were negative. Due to complications of CS, he was initially treated with cabergoline, but switched to osilodrostat due to intolerances. He is currently on 2 mg BID dose and 24-hr UFC has been normal since then (UFC 20 mcg/L, Cr 0.67 mg, UFC/Cr 12 mcg/mg/L). He continued to have uncontrolled hyperglycemia despite normalization of UFC. On his CGM data, he was in target range (70-180 mg/dL) 5% of the time despite using U-500R 95 units SC TID. Given his severe hyperglycemia and insulin resistance, he was switched to an AID system with U-500R and his time in target range improved over 60% after a month of use and his total daily dose of insulin decreased to less than 200 units. Conclusion: U-500R proved to be safe and effective with Omnipod 5 AID. To our knowledge, this is the first reported patient with CS using U-500R with Omnipod 5 AID. In patients without CS, the AID algorithm continuously kept BG well below the set target, especially overnight. Notably, our patient did not have this overnight hypoglycemia trend, which should be expected with his disease. We are hoping to increase the awareness of U-500R with AID systems, especially for patients with incurable CS. Reference:1.Aurora J Jr, Saraswat A. J Endocr Soc. 2023;7(Suppl 1):bvad114.873. Presentation: 6/3/2024