1977-P: Medical Spending Before and After GLP-1RA Initiation among Commercially Insured Adults Aged 18–64 Years with Type 2 Diabetes

Introduction and Objective: Use of GLP-1 receptor agonists (GLP-1 RA) has increased among commercially insured adults with type 2 diabetes (T2D), but research on spending impacts compared to non-users is limited. We estimated medical expenditure changes attributable to GLP-1 RA initiation. Methods: Using 2016-2023 MarketScan commercial claims, we identified adults aged 18-64 years with T2D and continuous enrollment for at least 2 years. GLP-1 RA users were individuals who initiated therapy in 2018 without prior GLP-1 RA history in the previous 2 years, used a GLP-1 RA for ≥6 months, and remained in the treatment group regardless of later discontinuation. Controls never used a GLP-1 RA and were matched 1:1 to users via propensity scores based on age, race/ethnicity, sex, comorbidities, baseline glucose-lowering medications, and pre-period health care utilization. Controls were assigned pseudo-index months drawn from the distribution of initiation months in 2018 among users. Quarterly total, prescription (including GLP-1 RAs), and non-prescription medical spending (2023 USD) were measured 24 months before through 60 months after initiation. Time on a GLP-1 RA was defined as the interval from the first fill through the end of the last observed fill plus days of supply, regardless of gaps in between. Spending changes attributable to GLP-1 RA initiation were estimated using two-way fixed-effects difference-in-differences models. Results: Groups were well balanced (n=2,910 for each group). GLP-1 RA users stayed on a GLP-1 RA for 639 days on average. GLP-1 RA initiation was associated with $1,642 higher total quarterly spending, driven by a $1,751 increase in prescription costs after adjustment. Mean inpatient and outpatient spending was $109 lower relative to controls. All differences in spending were statistically significant. Conclusion: Among commercially insured adults with T2D, GLP-1 RA initiation increases overall and drug spending, and modestly reduces non-drug medical expenditures, informing evaluations of long-term value. Disclosure Y. Wang: None. P. Zhang: None. Y. Shao: None. K. Bullard: None. R. Li: None. C.S. Holliday: None. O. Idubor: None.