Impact of Anti-obesity Medication Initiation and Duration on Weight Loss.

INTRODUCTION: Real-world studies of anti-obesity medication (AOM) use have shown lower adherence and persistence than clinical trials; however, the impact of this reduced adherence in real-world settings remains largely unexplored. This study aimed to evaluate the effects of AOM use, timing of initiation, and duration on 18-month weight loss outcomes in comprehensive obesity care practice, offering critical insights into the role of adherence in optimizing treatment efficacy. METHODS: This retrospective cohort study assessed the electronic health records of adults with a body mass index (BMI) ≥ 30 kg/menrolled in a digital obesity program for ≥ 18 months. Participants were categorized by AOM use, initiation timing (early vs. delayed), and duration (short vs. long). RESULTS: This study of 1282 participants showed that AOM users had greater weight reduction than non-users. Long- and short-duration AOM users experienced significantly more weight loss than short-duration users, with no difference between early and delayed starters. Second-generation semaglutide users were more likely to reach the 20% weight loss milestone, especially with longer use. CONCLUSION: Long-term AOM use significantly improved weight loss in comprehensive obesity care. Furthermore, the success of non-AOM users highlights the value of intensive behavioral programs, indicating the need for personalized treatment to optimize cost-effectiveness and outcomes.