Real-world use of semaglutide for obesity treatment: A cohort study in an integrated health care delivery system

BACKGROUND: Novel antiobesity medications have demonstrated significant weight loss in clinical trials. Data on real-world use of semaglutide are lacking. Such data are vital to inform health benefit design of this and other costly incretin mimetics, as well as inform patients of expected outcomes outside of clinical trials. OBJECTIVE: To evaluate real-world persistence and adherence to semaglutide for obesity treatment and impacts on weight loss. METHODS: The primary outcome was persistence to therapy. Secondary outcomes were adherence to therapy and its approved dosing schedule. Weight loss observations for all outcomes were also analyzed. This retrospective, cohort, observational study evaluated prescription and clinical data from a single health system between 2021 and 2024. The index date was defined as the first semaglutide claim filled for weight loss, and all refill data were obtained up to 12 months following. Electronic medical record data were collected at 6 and 12 months. Persistence was defined as the absence of any therapy gap exceeding 60 days within 12 months. Adherence was defined as proportion of days covered greater than or equal to 80%. Weight loss was calculated as percent change from baseline, defined as the collected weight closest to the index date. Multivariable logistic regression was used to identify factors independently associated with persistence and adherence at 12 months. RESULTS: A total of 393 patients were included. Throughout the 12-month follow-up period, 44% (172) of patients remained persistent and lost a mean of 13.8% of their baseline weight, compared with 6.4% for nonpersistent patients. At 12 months, 44% (175) patients were adherent and experienced 13% weight loss. For those closely following the approved titration schedule, a 12.5% average weight loss at month 12 was observed, almost double that of patients using other titration patterns (7.2% average weight loss at month 12). In multivariable logistic regression analyses, compared with male sex, female sex was associated with lower odds of persistence (odds ratio = 0.32; 95% CI = 0.14-0.75) and adherence (odds ratio = 0.33; 95% CI = 0.14-0.77), whereas race, ethnicity, and comorbidities were not statistically significantly associated with persistence or adherence. CONCLUSIONS: Less than 45% of patients were persistent or adherent to semaglutide for weight loss during the initial 12 months of use. The results of this study suggest that adding support measures and/or altering coverage criteria based on persistence or adherence patterns may be reasonable to consider. Efforts to promote persistence and adherence during the first year of treatment, as well as proper implementation of titration schedules, may lead to improved weight loss in patients using semaglutide.