Clinical and economic outcomes among injection-naïve patients with type 2 diabetes initiating dulaglutide compared with basal insulin in a US real-world setting: the DISPEL Study

Abstract

Aims: To report 1-year clinical and economic outcomes from the retrospective DISPEL (Dulaglutide vs Basal InSulin in Injection Naïve Patients with Type 2 Diabetes: Effectiveness in ReaL World) Study.

Materials and methods: This observational claims study included patients with type 2 diabetes (T2D) and ≥1 claim for dulaglutide or basal insulin between November 2014 and April 2017 (index date=earliest fill date). Propensity score matching was used to address treatment selection bias. Change from baseline in hemoglobin A1c (HbA1c) was compared between the matched cohorts using analysis of covariance; diabetes-related costs were analyzed using generalized linear models.

Results: Matched cohorts (903 pairs total; 523 pairs with complete cost data) were balanced in baseline characteristics with mean HbA1c 8.6%, mean age 54 years. At 1 year postindex, dulaglutide patients had significantly greater reduction in HbA1c than basal insulin (-1.12% vs -0.51%, p<0.01), lower medical costs ($3753 vs $7604, p<0.01), higher pharmacy costs ($9809 vs $6175, p<0.01), and similar total costs ($13 562 vs $13 779, p=0.76). Medical and total costs per 1% HbA1c reduction were lower for dulaglutide than basal insulin (medical: $3128 vs $12 673, p<0.01; total: $11 302 vs $22 965, p<0.01), while pharmacy costs per 1% HbA1c reduction were lower without reaching statistical significance ($8174 vs $10 292, p=0.15).

Conclusions: In this real-world study, patients with T2D initiating dulaglutide demonstrated greater HbA1c reduction compared with those initiating basal insulin. Although total diabetes-related costs were similar, the total diabetes-related costs per HbA1c reduction were lower for dulaglutide, highlighting the importance of evaluating effectiveness along with the economic impact of medications.

Keywords: HbA1c; adherence to medications; claims database analysis; insulin delivery.

Figure 1

Glycemic outcomes at 1 year postindex among patients initiating dulaglutide versus basal insulin.*Significant difference between dulaglutide versus basal insulin with p value <0.05. Estimates obtained using ANCOVA with baseline HbA1c level (continuous variable) as covariate.

Figure 2

Longitudinal changes in HbA1c among matched dulaglutide initiators versus basal insulin initiators (MMRM).*Significant difference between dulaglutide versus basal insulin with p value <0.05. Results are from a mixed-effects model with repeated measurements (MMRM). Data represent least square mean ± 95% confidence limit. Baseline reflects HbA1c results obtained between (index date - 183 days) and (index date + 14 days); the value closest to index date was chosen if there were multiple values. 3/6/9/12 months reflects HbA1c results obtained between windows of ±45 days around index date +92/183/274/365 days, with the value closest to and prior to the anchor date chosen if there were multiple values. Point estimates are available in online supplementary appendix table 6.

Figure 3

Healthcare costs in USD per 1% HbA1c reduction at 1 year Post-Index*Significant difference between dulaglutide versus basal insulin with p value <0.05. Costs per 1% HbA1c reduction were calculated from the mean cost across all patients, divided by mean HbA1c reduction. Error bars represent 95% CIs obtained by bootstrapping with 5000 replications.