OBJECTIVE: The safety and efficacy of the GLP-1 receptor agonists exenatide BID (exenatide) and liraglutide for treating type 2 diabetes mellitus (T2DM) have been established in clinical trials. Effective treatments may lower overall treatment costs. This study examined cost offsets and medication adherence for exenatide vs liraglutide in a large, managed care population in the US.
METHODS: This was a retrospective cohort analysis comprising adult patients with T2DM who initiated exenatide or liraglutide between 1/1/2010 and 6/30/2010 and had 6 months pre-index and post-index continuous eligibility. Patients were propensity score-matched to controls for baseline differences. Medication adherence was measured by proportion of days covered (PDC). Paired t-test and McNemar's test were used to compare outcomes.
RESULTS: Matched exenatide and liraglutide cohorts (n=1347 pairs) had similar average total 6-month follow-up costs ($6688 vs $7346). However, exenatide patients had significantly lower mean pharmacy costs ($2925 vs $3272, p<0.001). Among liraglutide patients, patients receiving the 1.8 mg dose had significantly higher average total costs compared to those receiving the 1.2 mg dose ($8031 vs $6536, p=0.026), with higher mean pharmacy costs in the 1.8 mg cohort ($3935 vs $3146, p<0.001). There were no significant differences in inpatient or outpatient costs or medication adherence between groups (mean PDC: exenatide 56% vs liraglutide 57%, p=0.088).
LIMITATIONS: The study assumed that all information needed for case classification and matching of cohorts was present and not differential across cohorts. The study did not control for covariates that were unavailable, such as HbA1c and duration of diabetes.
CONCLUSIONS: Patients initiating exenatide vs liraglutide for T2DM had similar medication adherence and total healthcare costs; however, exenatide patients had significantly lower total pharmacy costs. Patients prescribed 1.8 mg liraglutide had significantly higher costs compared to those on 1.2 mg.
