Selective Prescribing of First‐Line SGLT2 Inhibitor and GLP ‐1 RA in Adults With Severe Mental Illness and Type 2 Diabetes

ABSTRACT Purpose SGLT2 inhibitors (SGLT2i) and GLP‐1 receptor agonists (GLP‐1 RA) provide cardiovascular (CV) benefits, but their first‐line use among adults with severe mental illness (SMI) is not well characterized. We evaluated selective prescribing of SGLT2i, GLP‐1 RA, and metformin among adults with SMI and type 2 diabetes (T2D). Methods Using 2017–2022 Medicare claims, we identified adults with SMI and T2D who initiated first‐line SGLT2i, GLP‐1 RA, or metformin during 1/1/2018–12/31/2021. By calendar year, standardized mean differences (SMD) assessed baseline characteristic differences, and propensity score overlap coefficients (OVL) assessed group comparability between SGLT2i or GLP‐1 RA initiators and metformin initiators. Results We identified 1322 SGLT2i, 2306 GLP‐1 RA, and 21 144 metformin initiators. From 2018 to 2021, SGLT2i initiators shifted from younger to older than metformin initiators (SMD, −0.11 to 0.19), while differences in CVD (0.10 to 0.50) and CKD (0.18 to 0.62) increased. GLP‐1 RA initiators consistently had higher prevalence of obesity (SMD, 0.33 to 0.41) and CKD (0.42 to 0.28) than metformin initiators. Compared with metformin initiators, both SGLT2i and GLP‐1 RA initiators had lower prevalence of schizophrenia, antipsychotic use, and recent psychiatrist visits but higher prevalence of major depressive disorder; these differences generally persisted over time. OVL increased from 42.7% to 50.7% for SGLT2i and from 42.3% to 50.0% for GLP‐1 RA versus metformin. Conclusions First‐line SGLT2i and GLP‐1 RA prescribing among adults with SMI was selective according to cardiometabolic and mental health‐related characteristics. Future comparative studies should account for these differences and temporal prescribing changes to mitigate confounding.