Introduction & Objective: Tirzepatide is a novel GIP/GLP-1 receptor agonist recently approved for diabetes and chronic weight management. Its effects on bodyweight loss are well-established. However, its effect on lean body mass (LBM) and fat mass (FM) loss is less established. This review aims to assess the effects on LBM and FM in patients treated with tirzepatide, with or without type 2 diabetes (T2DM). Methods Following PRISMA guidelines, this systematic review included data from randomized controlled and observational studies evaluating tirzepatide’s effect on body composition. The ratio of FM/LBM loss was then assessed.
Results: Of 5847 prospective abstracts, three studies were included in the final analysis (Table 1). The FM/LBM loss ratio in patients with T2DM treated with tirzepatide doses of 5-15 mg ranged from 2.9-6.1 across two studies. Ratios could not be calculated from the SURMOUNT-1 trial but a change from baseline of -33.9% in FM and -10.9% in LBM in patients without diabetes was reported. Significant heterogeneity existed among the included studies due to varying therapy duration, dosing schedules, inclusion criteria, and body composition assessment modalities.
Conclusion: Data is limited on tirzepatide’s effect on LBM loss, but our study suggests a decrease in LBM with its use. Further research should address LBM loss with these therapies. Clinicians should counsel patients on methods to preserve LBM.
M. Bodenstab: None. M. Iskander: None. J. Mintz: None. M.P. Lieberman-Ulm: None. D. Soliman: None. R.J. Galindo: Consultant; Abbott. Other Relationship; Dexcom, Inc. Consultant; Bayer Inc. Other Relationship; Novo Nordisk, Eli Lilly and Company. Consultant; Boehringer-Ingelheim, AstraZeneca.
