Cost and Utilization Outcomes After Exclusion of Dipeptidyl Peptidase-4 Inhibitors and Other Diabetes Drug Category Changes in a Self-Funded, State Employee Managed Care Plan

Dipeptidyl peptidase-4 (DPP-4) inhibitors have repeatedly shown no reduction in the clinical outcomes of cardiovascular death, myocardial infarction, stroke, or all-cause mortality. Because the treatment of diabetes is generally one of the top drug categories by cost to health plans and self-funded employers, it is necessary to evaluate coverage of DPP-4 inhibitors, considering their lack of cardiovascular benefit relative to other treatment options. To describe the cost and utilization outcomes of drugs used to treat diabetes after exclusion of DPP-4 inhibitors in a self-funded managed care plan. This study was a retrospective, descriptive analysis of the cost and utilization outcomes after exclusion of DPP-4 inhibitors. Pharmacy claims data and plan membership were analyzed 6 months before DPP-4 inhibitor exclusion (preperiod: December 1, 2016-May 31, 2017) and 6 months after DPP-4 inhibitor coverage ended for all users (postperiod: September 1, 2017-February 28, 2018). The allowed amount, which is not influenced by overlapping plan copay changes, and utilization per member per month (PMPM) were used to estimate the effect of the DPP-4 inhibitor benefit exclusion on plan costs for the antidiabetic class. From preperiod to postperiod, all DPP-4 inhibitor products decreased in utilization by 3.02 claims per 1,000 members per month (PTMPM). Glucagon-like peptide-1 receptor agonists, insulins, sodium-glucose cotransporter-2 inhibitors, and thiazolidinedione claims increased by 0.72, 0.43, 0.30, and 0.48 claims PTMPM, respectively, but there was an absolute decrease of 1.35 claims for antidiabetic medications per 1,000 plan members. However, the days supplied PMPM increased from 2.55 to 2.61 (2.3%) days. Allowed amount PMPM increased by $0.27 from $12.19 in the preperiod to $12.31 in the postperiod (2.2%). However, it is estimated that drug cost inflation accounted for over half of the PMPM increase in allowed costs. The observed increase in the allowed amount PMPM was attributable in similar amounts by an increase in utilization of medications with higher cost per day supplied and higher drug prices. Future research will evaluate patient-level effects of this benefit change in terms of antidiabetic medication utilization and outcomes. No outside funding supported this study. Davis, Bemberg, and Johnson currently work for or previously worked for the UAMS Evidence-Based Prescription Drug Program, which advises the Employee Benefits Division (EBD) on pharmacy