Prescribing SGLTis and GLP-1 RAs for Patients With Type 2 Diabetes, Guideline Updates, and Longitudinal Knowledge Assessment Scores

Importance: Sodium-glucose cotransporter 2 inhibitors (SGLT2is) and glucagon-like peptide-1 receptor agonists (GLP-1 RAs) reduce cardiovascular and kidney events in patients with type 2 diabetes (T2D) who have established atherosclerotic cardiovascular disease, heart failure, or chronic kidney disease, yet prescribing to these patients remains low. Objectives: To describe temporal patterns in SGLT2i and GLP-1 RA prescribing before and after the 2019 American Diabetes Association (ADA) guideline update and to assess whether these patterns differed across physicians with subsequently measured different first-year American Board of Internal Medicine Longitudinal Knowledge Assessment (LKA) scores. Design, Setting, and Participants: This serial cross-sectional study was conducted from October 2025 through January 2026, using 2017 to 2022 traditional Medicare claims. Endocrinologists first participating in the 2022 to 2023 LKA and the Medicare beneficiaries with T2D they treated were included. Exposure: Time relative to the 2019 ADA guideline update. Main Outcomes and Measures: The annual patient-year SGLT2i and GLP-1RA guideline-targeted and nontargeted patient fill rates were the main outcome. Linear physician, year, and target subgroup fixed-effects regression models were estimated, with patient demographic and health risk controls to evaluate within-physician associations between guideline-targeted vs nontargeted patient-year fill rates each year relative to 2018 (the year before the guideline update). The variation in these associations across first-year LKA score quartiles was also evaluated. Results: A total of 1061 endocrinologists caring for 177 284 Medicare beneficiaries with T2D (mean [SD] age, 74.5 [6.1] years; mean [SD] 54.4% [49.8] female; mean [SD] 9.3% [29.1] Black, 6.6% [24.9] Hispanic, and 76.2% [42.6] White non-Hispanic) were included. Adjusted guideline-targeted SGLT2i and GLP-1 RA fill rates increased monotonically from 2018 to 2022 by 11.4 percentage points (pp) (95% CI, 10.5 to 12.3 pp; P < .001) and 2.4 (95% CI, 1.4 to 3.3 pp; P < .001) for SGLT2is and GLP-1 RAs targeted vs nontargeted subgroups, respectively. The associated SGLT2i increase was 3.9 pp (95% CI, 1.4 to 6.5 pp) larger for patients of endocrinologists with top vs bottom LKA quartile scores (P = .003), but for GLP-1 RAs, this association was not statistically significant with wide confidence intervals. Conclusions and Relevance: In this cross-sectional study, 2019 ADA guideline update timing was associated with substantially increased SGLT2i and moderately increased GLP-1 RA guideline-concordant prescribing among guideline-targeted, compared with nontargeted, patient subgroups by 2020. These increases in SGLT2i guideline congruent prescribing were associated with higher subsequently measured first-year LKA scores.