Real-world 6-month persistence, adherence, and effectiveness of GLP-1 medications for overweight and obesity in a Medicaid population.
This retrospective, claims-based observational study examined real-world persistence, adherence, and weight-loss effectiveness of GLP-1 receptor agonists (semaglutide/Wegovy) and the dual GLP-1/GIP agonist (tirzepatide/Zepbound) among 7,493 adults enrolled in Massachusetts Medicaid (MassHealth) who initiated treatment between July and December 2024. At 6 months, the study found moderate rates of persistence (60.8%, defined as no gap greater than 56 days between fills) and adherence (60.1%, defined as proportion of days covered ≥80%). Male sex and younger age were among the member-specific factors associated with lower persistence and adherence. In a subgroup of highly persistent and adherent members with prior authorization recertification data, both tirzepatide and semaglutide were associated with at least 5% body weight reduction at 6 months. Key limitations include the retrospective claims-based design, which cannot establish causality, the restriction to a Medicaid population limiting generalizability, and the weight-loss outcome being measured only in a select, highly adherent subgroup rather than the full cohort.
Why this grade: Although the study involves a large real-world human sample (n=7,493), its retrospective, non-randomized, claims-based design and restriction to a single state Medicaid population limit causal inference and generalizability.
Background Glucagon-like peptide-1 (GLP-1) receptor agonists, including a dual GLP-1/glucose-dependent insulinotropic polypeptide (GIP) agonist, have expanded treatment options for overweight and obesity. However, real-world data within Medicaid populations remain limited. Objective To assess 6-month persistence, adherence, and effectiveness of GLP-1 and GLP-1/GIP therapies among Massachusetts Medicaid (MassHealth) members. Methods This retrospective, claims-based analysis identified continuously enrolled MassHealth adults, with or without diabetes, initiating GLP-1 or GLP-1/GIP treatment with semaglutide (Wegovy) or tirzepatide (Zepbound) between July 1, 2024, and December 31, 2024. The co-primary outcomes were persistence, defined as no more than 56 days between fills, and adherence, defined as proportion of days covered (PDC) of at least 80%. A key secondary outcome examined the rate at which a subgroup of members achieved at least a 5% reduction in body weight from baseline as documented on prior authorization (PA) recertification at 6 months. Results Among 7,493 members, rates of persistence and adherence to treatment were 60.8% and 60.1%, respectively. Member-specific factors associated with lower rates of persistence and adherence included male sex, age ( Conclusions At 6 months, MassHealth members showed moderate persistence and adherence to GLP-1 or GLP-1/GIP treatment. Tirzepatide and semaglutide were effective in producing significant weight loss at 6 months among a subgroup of highly persistent and adherent members.
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