SUN-521 - Benefit of Tirzepatide Treatment in A Patient with Type 1 Diabetes on Insulin Pump with Automated Insulin Delivery

Background/

Introduction:

While Glucagon-like Peptide-1 Receptor Agonists (GLP-1 RA) have become treatment mainstays for Type 2 Diabetes (T2DM), their role in the treatment of Type 1 Diabetes (T1DM) is less well characterized. Like the general population, patients with T1DM may develop obesity and insulin resistance and, thus, benefit from GLP-1 RA. We present a case of a patient with T1DM on an insulin pump with Automated Insulin Delivery (AID) whose glucose control improved and insulin requirement decreased after GLP-1 RA treatment with significant weight loss.

Clinical

Case:

The patient was a 39-year-old female with T1DM diagnosed at age 10, managed on a Tandem insulin pump AID and continuous glucose monitor (CGM). Her weight on initial visit with us was 99.3 kg [Body Mass Index (BMI) 35.3 kg/m²]. 14-day CGM data report showed 55% glucose in target range, 38% high (>180 mg/dL), 7% low ( < 70 mg/dL). Her average daily insulin requirement was 52 units. She was started on Liraglutide and transitioned within six months to Tirzepatide (off-label use for T1DM management). Eighteen months after initiation of GLP-1 RA, the patient’s weight decreased to 61.2 kg (BMI 21.8 kg/m²). Her average daily insulin reduced to 33 units, and her glucose control improved: 14-day CGM data report showed 84% in target range, 14% high, 2% low. She tolerated gradually increased Tirzepatide dose well; she has been on 12.5mg weekly for over 9 months so far, maintaining weight loss and excellent glucose control.

Discussion:  

GLP-1 RAs are approved to treat T2DM and obesity; some also confer cardiovascular and renal protection. Because GLP-1 RAs’ benefits may stem at least partly from enhanced insulin secretion, patients with T1DM may not reap full benefit. Nonetheless, previous case series and small studies demonstrated similar benefits of GLP-1 RAs in T1DM with obesity and insulin resistance. Our case highlights how GLP-1 RAs can decrease insulin requirement and improve glucose control with reduced glycemic variability through mechanisms including improving insulin sensitivity and weight loss despite lack of endogenous insulin secretion. T1DM patients who may benefit from such off-label use include those with elevated BMI; high insulin requirements; and large glucose variability. Potential risks of GLP-1 RA use in T1DM include increased risk of ketosis associated with overly rapid insulin reduction or decreased appetite; hypoglycemia, if insulin isn’t adequately reduced when appetite decreases; and gastrointestinal side effects. Therefore, patients must be closely monitored with expert guidance. More studies are needed to assess the long-term efficacy and safety of GLP-1 RAs in T1DM and to improve accessibility of these medications to patients who may benefit.

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