Sex, Not Age, Predicts Weight Loss Outcomes With Tirzepatide: A Retrospective Analysis.

OBJECTIVE: This study assessed the impact of sex and age on weight loss outcomes in patients receiving tirzepatide in real-world clinical practice. METHODS: We conducted a retrospective cohort study of adults with overweight or obesity who initiated tirzepatide at Mayo Clinic between June 2022 and May 2024 and completed ≥ 12 months of continuous therapy. Primary outcome was total body weight loss percentage (TBWL%) at 15 months, stratified by sex and age groups (≤ 45, 46-59, ≥ 60 years). RESULTS: Among 1039 patients (57% women; mean age 56 ± 11 years), women achieved significantly greater TBWL% than men after 15 months of treatment (15.1% vs. 10.7%, p < 0.001). Patients aged ≤ 45 years had greater weight loss than those ≥ 60 years (15.1% vs. 12.3%, p = 0.024). In multivariable analyses, greater weight loss was independently associated with female sex, absence of type 2 diabetes, no prior obesity medication use, no concomitant weight gain-promoting medications, and higher tirzepatide dosage. Age was not an independent predictor. CONCLUSIONS: Sex, but not age, predicted weight loss with tirzepatide among individuals using the medication continuously for ≥ 12 months. These findings underscore the importance of incorporating sex-specific considerations into personalized obesity treatment strategies.