BACKGROUND: The purpose of this case report is to describe the use of tirzepatide, a glucose-dependent insulinotropic polypeptide/glucagon-like peptide-1 receptor agonist, in a patient with type 1 diabetes mellitus (T1DM) and obesity.
CASE SUMMARY: A 23-year-old female with T1DM since the age of 10 years was referred to an endocrinology clinic for specialized diabetes care with a pharmacist owing to increasing insulin requirements and resistance. At baseline, the patient weighed 195 pounds (86.64 kg), which had increased significantly by approximately 40 pounds in the last year, and had a body mass index of 38 kg/mand hemoglobin A1c (HbA1c) level of 7.4%. She used hybrid closed loop insulin pump technology with continuous glucose monitoring in 100% automation mode. The patient used on average 55.4 units of basal insulin and 26.5 units of bolus per day (total daily dose, 81.9 units) with a time in range (TIR) of 31%. The patient was started on tirzepatide 2.5 mg weekly and titrated to 7.5 mg weekly with 4-week dose titrations. After 12 weeks, the patient's TIR had doubled to 61% with improvements in glucose variability, insulin requirements had decreased to 57.6 units per day, HbA1c had decreased to 6.9%, daily carbohydrates had decreased by approximately 24%, and weight had decreased to 188 pounds (-7 lbs).
PRACTICE IMPLICATIONS: With additional studies, tirzepatide may be a safe and effective option for patients with T1DM and obesity to improve glycemic control, reduce insulin requirements, and promote weight loss.