Studies examine prescribing patterns, access issues with newer diabetes drug classes
Use of tirzepatide, glucagon-like peptide-1 receptor agonists, and sodium-glucose cotransporter-2 inhibitors increased sharply in the U.S. from 2021 to 2023, one study found, while another noted inequities in availability of newer medications for type 2 diabetes.
Recent studies evaluated prescribing patterns for diabetes drugs after recent FDA approvals and availability of cardioprotective medications for patients with type 2 diabetes on Medicaid.
In a population-based cohort study, researchers used U.S. claims data for adults with and without type 2 diabetes to describe trends in insurance claims for glucose- and weight-lowering medications after tirzepatide was approved by the FDA. Monthly trends in medication dispensation before and after tirzepatide entered the market were analyzed, and uptake of tirzepatide was compared with initial postapproval uptake of other glucose- and weight-lowering medications. The results were published April 15 by Annals of Internal Medicine.
By December 2023, tirzepatide dispensations made up 12.3% of all dispensations of glucose-lowering drugs in patients with type 2 diabetes, the study found. The researchers observed similar patterns for sodium-glucose cotransporter-2 (SGLT-2) inhibitors (increasing from 14.5% in 2021 to 24.4% in 2023) and GLP-1 receptor agonists (from 19.5% to 28.5%). Among adults without diabetes who were prescribed weight-lowering medications, dispensations of tirzepatide (0.0% to 40.6%) and semaglutide, 2.4 mg, increased sharply from 2021 to 2023 (0.0% to 32.2%), but semaglutide, 2.0 mg, was the most frequently dispensed weight-lowering medication, increasing from 37.8% to 45.7%. Dispensations of other glucose- and weight-lowering medications decreased during this time period. Trends were similar among incident users, and uptake of tirzepatide was more rapid and sustained than that of other drugs immediately after approval.
The authors noted that some cases of diabetes could have been misclassified and that treatment adherence and medication sequencing were not evaluated, among other limitations. “In this population-based cohort study of commercially insured U.S. adults, use of tirzepatide, GLP-1 [receptor agonists], and [SGLT-2 inhibitors] increased sharply between 2021 and 2023, whereas use of other glucose- and weight-lowering therapies declined,” they wrote. “These findings highlight the rapidly shifting landscape of [glucose-lowering medication] and [weight-lowering medication] use in the United States.”
Another study, published April 22 by Annals, looked at the availability of cardioprotective medications for type 2 diabetes in patients on Medicaid. Researchers used publicly available data from Medicaid fee-for-service plans and Medicaid managed care organization (MCO) plans with comprehensive coverage to assess unrestricted availability of SGLT-2 inhibitors and GLP-1 receptor agonists, with dipeptidyl peptidase-4 (DPP-4) inhibitors as a benchmark.
Among 50 Medicaid fee-for-service plans, 40 (80%) had unrestricted availability of SGLT-2 inhibitors, 30 (60%) had unrestricted availability of GLP-1 receptor agonists, and 42 (84%) had unrestricted availability of DPP-4 inhibitors. Availability of either or both SGLT-2 inhibitors and GLP-1 receptor agonists was unrestricted in 41 (82%) and 29 (58%) plans, respectively. Among 273 Medicaid MCO plans, 182 (67%) had unrestricted availability of SGLT-2 inhibitors, 131 (48%) had unrestricted availability of GLP-1 receptor agonists, and 204 (75%) had unrestricted availability of DPP-4 inhibitors. Availability of either or both SGLT-2 inhibitors and GLP-1 receptor agonists was unrestricted in 184 (67%) and 129 (47%) plans, respectively. Tirzepatide was almost completely restricted. There were an estimated 6,798,266 adult enrollees with diabetes in the Medicaid program, and of these, an estimated 1.7 million (25.1%) and 2.72 million (40.0%) had restricted availability of SGLT-2 inhibitors and GLP-1 receptor agonists, respectively, the authors noted.
The study assessed formulary coverage in March 2024 and plan-level data on diabetes prevalence were not available, among other limitations. The authors concluded that in their study, 25% of Medicaid enrollees with diabetes had restricted availability of an SGLT-2 inhibitor and 40% had restricted availability of a GLP-1 receptor agonist, access limitations that were driven by greater restrictions within the Medicaid MCO program, with marked variability across plans and states. Tirzepatide was almost entirely restricted nationwide, and DPP-4 inhibitors were more widely available although they lack similar cardioprotective benefits, the authors said.
“Our findings call attention to the need to continue monitoring unrestricted availability for these medications in Medicaid, particularly for tirzepatide (which remains almost entirely restricted as of 2024) given its superior effectiveness among GLP-1 [receptor agonist] medications and expanding clinical indications,” they wrote. “Because of substantial underuse among Medicaid enrollees and sizeable geographic variation in unrestricted availability, further research is needed to study the explicit link between formulary restrictions and receipt of prescriptions to inform if plan coverage can be a key policy lever to improve health outcomes and mitigate inequities.”