MON-720 Beyond Age: Sex as the Key Weight Loss Predictor with Tirzepatide

Abstract Disclosure: R. Castaneda: None. D. Bechenati: None. R.D. Rivera Gutierrez: None. M.A. Espinosa: None. J.L. Villamarin: None. E. Tama: None. J.L. Meek: None. P. Bennett: None. A. Acosta: Novo Nordisk, Gila Therapeutics, Amgen Inc, Regeneron Pharmaceuticals, Boehringer Ingelheim, Rhythm Pharmaceuticals, General Mills, Currax, Nestle, Phenomix Sciences, Busch Health, RareDiseases, National Institute of Health, Vivus Pharmaceuticals, Apollo Endosurgery, Satiogen Pharmaceuticals, Spatz Medical. S. Faubion: Era Women’s Health Platform, PriMed, MedAll, AiCME, Medscape, Weight Watchers. C. Shufelt: Bayer Advisory Board. M.D. Hurtado: Novo Nordisk, National Institute of Health, Phenomix. Introduction: Tirzepatide, a dual GIP and GLP-1 receptor agonist, is an FDA-approved medication demonstrating the highest efficacy for weight loss among currently available treatments. However, the influence of sex and age on weight loss outcomes with tirzepatide remains unclear. Objective: To investigate the influence of sex and age on weight loss outcomes in patients treated with tirzepatide. Methods: This retrospective study evaluated weight loss outcomes associated with tirzepatide across sex and age groups. Patients with active malignancy, prior bariatric surgery, or concurrent anti-obesity medication were excluded. The primary endpoint was total body weight loss percentage (TBWL%) at 15 months by sex and age. The influence of age was analyzed as a categorical (≤45, 46-59, ≥60 years) and continuous variable. Secondary outcomes included TBWL% at 3, 6, 9, and 12 months by sex and age. Data were analyzed using independent t-tests, one-way ANOVA, and multivariate regression; results are reported as mean ± standard deviation. Results: The study included 1033 patients (57.1% female; mean age 56 ± 11 years; mean BMI, 37.7 ± 8 kg/m2). By age category, 18.8% (196) were ≤45 years (35.7% males, 64.3% females), 45.9% (473) were 46-59 years (42.7% males, 57.3% females), and 35.3% (364) were ≥60 years (54.7% males, 45.3% females). At all timepoints, TBWL was significantly greater in females compared to males at all timepoints. At 15 months females had a higher TBWL than males: 15.3% ± 10, n=340, vs. 10.2% ± 8, n=244, (p < 0.001). Among females, premenopausal women achieved a higher TBWL than postmenopausal women: 16.9% ± 10 vs 14.4% ± 9, p = 0.04. Analysis by age groups revealed a trend toward higher TBWL in younger patients that did not reach statistical significance (p = 0.152): ≤45 years (14.7% ± 10%), 46-59 years (12.9% ± 10%), and ≥60 years (12.7% ± 9%). After adjusting for baseline age, BMI, and diabetes status, sex remained a strong predictor for weight loss outcomes (PE= 4.5, 95% CI [2.96, 5.97], p < 0.001), following type 2 diabetes status (PE= 4.8, 95% CI [3.0, 6.7], p < 0.001). Conclusion: Sex but not age was a strong predictor of weight loss with tirzepatide. Female sex was associated with greater weight loss than male sex. These results emphasize the importance of considering sex-specific factors in weight loss strategies and warrant further investigation into the underlying biological mechanisms. Differential weight loss by menopause, underscores the role of sex hormones. Presentation: Monday, July 14, 2025