Health care utilization and costs associated with switching from DPP-4i to GLP-1RA or SGLT2i: an observational cohort study

BACKGROUND: Because of improved clinical outcomes, recent American Diabetes Association guidelines recommend the use of newer antidiabetic agents—glucagon-like peptide-1 receptor agonists (GLP-1RA) and sodium-glucose cotransporter 2 inhibitors (SGLT2i)—by those with cardiovascular disease. It is unclear, however, how switching to these newer agents affects health care utilization and costs. OBJECTIVE: To compare health care utilization and costs between users of dipeptidyl peptidase-4 inhibitors (DPP-4i) who switch to GLP-1RA or SGLT2i and nonswitchers. METHODS: We used claims data from a large pharmacy benefit manager. Patients included were commercially insured adults with type 2 diabetes and a prescription claim for DPP-4i in 2016 or 2017. Using propensity score methods, we matched patients who switched to SGLT2i or GLP-1RA with those who remained on DPP-4i. Among matched samples, we conducted multivariable negative binomial regression to examine differences in the incidence of inpatient and emergency room (ER) visits and generalized linear regression to examine differences in health care costs. RESULTS: Among 47,953 patients who used DPP-4i in 2016 and 2017, 507 switched to SGLT2i and 808 switched to GLP-1RA. Propensity score matching of 1:6 resulted in 3,042 nonswitchers/507 switchers for the SGLT2i cohort and 4,848 nonswitchers/808 switchers for the GLP-1RA cohort. Switchers to SGLT2i experienced a 39% reduction (incidence rate ratio [IRR] = 0.61, 95% CI = 0.38-0.96), and GLP-1RA switchers experienced a 29% reduction (IRR = 0.71, 95% CI = 0.52-0.97) in inpatient hospitalizations. ER visit rates did not differ significantly between switchers and nonswitchers. Switchers to SGLT2i did not have statistically significant differences in medical or pharmacy costs compared with DPP-4i users, while switchers to GLP-1RA had significantly higher total pharmacy costs (adjusted difference of $2,453.10, 95% CI = $1,837.20-$3,069.00). CONCLUSIONS: Switching from DPP-4i to GLP-1RA or SGLT2i was associated with fewer hospitalizations; however, higher pharmacy costs may outweigh savings from reduced hospitalizations, especially for GLP-1RAs. As newer diabetes guidelines steer specific populations to these drug classes, it is important to optimize drug pricing to realize their true value.