Costs for commercially insured adults prescribed second-line diabetes medications

To examine differences in health care costs associated with choice of second-line antidiabetes medication (ADM) for commercially insured adults with type 2 diabetes.

Retrospective cohort study with multiple pretests and posttests.

Included patients initiated second-line ADM therapy between 2011 and 2015, with variable follow-up through 2017. The 6 index medication classes were sulfonylureas, dipeptidyl peptidase-4 (DPP-4) inhibitors, glucagon-like peptide-1 receptor agonists (GLP-1 RAs), basal insulin, sodium-glucose cotransporter-2 (SGLT-2) inhibitors, and thiazolidinediones (TZDs). Multivariable regression models compared between-class changes in adjusted quarterly costs after second-line ADM initiation.

The study cohort included 34,963 adults. Most were prescribed a sulfonylurea (46.0%) or DPP-4 inhibitor (30.4%). Adjusted quarterly index medication costs were significantly higher for all patients receiving nonsulfonylurea medications, ranging from $108 (95% CI, $99-$118) for TZDs to $742 (95% CI, $720-$765) for GLP-1 RAs. Changes in quarterly total health care costs were significantly higher for all nonsulfonylurea classes. Conversely, changes in quarterly nonpharmacy medical costs were significantly lower for patients receiving DPP-4 inhibitors (-$67; 95% CI, -$92 to -$43), GLP-1 RAs (-$43; 95% CI, -$85 to -$1), and SGLT-2 inhibitors (-$46; 95% CI, -$87 to -$6); changes in all other quarterly costs besides the index medication were significantly lower for patients receiving DPP-4 inhibitors (-$60; 95% CI, -$94 to -$26) and SGLT-2 inhibitors (-$113; 95% CI, -$169 to -$57).

The higher cost of nonsulfonylurea medications was the main driver of relative increases in total costs. Relative decreases in nonpharmacy medical costs among patients receiving newer ADM classes reflect these medications' potential value.