Abstract
Disclosure: J. Zinn: None. L. Poretsky: None.
Background: Multiple studies have demonstrated that treatment with tirzepitide results in significant improvement in HgbA1c as well as meaningful weight loss. Although the loss of skeletal muscle mass has been well described with the use of GLP-1 receptor agonists, there is little information regarding the effect of dual GLP-1/GIP receptor agonist tirzepitide on skeletal muscle mass. Clinical Case: A 68- year old male presented with a weight of 204.9 lbs and a BMI of 31.2 kg/m2. On exam, fat distribution was primarily central. Patient had a history of prediabetes, with an HgbA1c of 5.9%. He was unable to lose weight using lifestyle modifications, despite multiple meetings with a registered dietitian and consistent exercise of daily 3-6 mile walks. In the past, he used dulaglutide and semaglutide but had to discontinue these medications because of gastrointestinal side effects such as nausea and abdominal cramping. In June 2022, body composition (assessed using seca mBCA 514) demonstrated total weight of 204.9 lbs, BMI of 31.3 kg/m2, fat mass of 73.5 lbs (35.9%), fat-free mass of 131.4 lbs (64.1%), and skeletal muscle mass of 63.8 lbs (31.1%). He initiated Tirzepitide 2.5 mg weekly and maintained this dose for the duration of his treatment. Over nine months, total body weight decreased by 28.7 lbs or 13.9%. BMI decreased to 26.6 kg/m2 (at this point indicative of overweight status rather than obese). HgbA1c decreased to 5.3% (at this point no longer in the pre-diabetes range). Fat mass decreased by 18.9 lbs or 25.8%. Skeletal muscle mass decreased by 9.9 lbs or 15.5%. During this presentation we will provide a detailed time course of various metabolic and body composition parameters in this case and review relevant literature. Conclusion: We conclude that at least in some cases of patients treated with tirzepitide, up to 1/3 of lost body weight may be due to the loss of skeletal muscle mass. We suggest that, in addition to weight, serial body composition determinations should be obtained in patients on tirzepitide. It remains to be determined if adequate protein consumption and strength based exercise would ameliorate skeletal muscle mass loss observed with tirzepitide treatment. Reference: (1) Jastreboff AM, Aronne LJ, Ahmad NN, et al. Tirzepatide once weekly for the treatment of obesity. New England Journal of Medicine. 2022;387(3):205-216. doi:10.1056/nejmoa2206038
Presentation: 6/1/2024