Clinical and economic outcomes among patients with diabetes mellitus initiating insulin glargine pen versus vial.

BACKGROUND: Insulin pens may help patients reach glycated hemoglobin (HbA1c) target levels, but a substantial proportion of patients continue to use insulin vials/syringes. The objective of the current study was to evaluate real-world clinical and economic outcomes of patients with type 2 diabetes mellitus (T2DM) initiating insulin glargine via pen delivery (pen) or vial/syringe (vial) within a large managed-care population in the United States.

METHODS: This retrospective administrative claims study used data on adult, insulin-naïve patients with T2DM treated with ≥ 1 oral antidiabetic or glucagon-like peptide-1 receptor agonist at baseline. The index date was the earliest pen or vial prescription date. Propensity score matching (1:1) of patients in the pen and vial cohorts was used when comparing 1-year outcomes, including treatment persistence and adherence, HbA1c levels, hypoglycemia rates, and all-cause and diabetes-related health care costs (computed as paid amounts on claims).

RESULTS: Patients in the matched cohorts (n = 733 per cohort) were well balanced with regard to demographics (mean age 52 years; 43% women), clinical measures (mean HbA1c level, 9.4%; mean Quan-Modified Charlson Comorbidity Index score, 0.9), and health care utilization at baseline. Following initiation of insulin glargine, pen patients were more persistent (60.6% vs 50.1%; P < 0.001) and adherent (medication possession ratio, 0.73 vs 0.57; P < 0.001), with lower HbA1c levels during follow-up (mean adjusted change, -1.05 vs -0.73; P < 0.001), compared with vial patients. Hypoglycemic events occurred at similar rates across pen and vial cohorts (3.8% vs 5.2%, respectively; P = 0.21). Study drug costs were higher among pen users ($1164 vs $762, respectively; P < 0.001), but this did not translate into higher total all-cause or diabetes-related costs.

CONCLUSION: For patients with diabetes newly initiating insulin glargine, using an insulin pen device was associated with increased therapy persistence and adherence, and lower HbA1c levels relative to vial/syringe, without increasing total all-cause or diabetes-related costs.