Long-term clinical and economic outcomes associated with liraglutide versus sitagliptin therapy when added to metformin in the treatment of type 2 diabetes: a CORE Diabetes Model analysis.

BACKGROUND: A recent open-label, parallel group trial showed that liraglutide is superior to sitagliptin for reduction of HbA1c, and is well tolerated with minimum risk of hypoglycemia. Although these findings support the use of liraglutide as an effective GLP-1 agent to add to metformin, the value of liraglutide needs to be quantified in the framework of a cost-effectiveness (CE) analysis in a US setting. OBJECTIVE: This current study sets out to assess the long-term cost-effectiveness outcomes of liraglutide vs sitagliptin based on treatment effects data from the 1860-LIRA-DPP-4 52-week trial. METHODS: The IMS CORE Diabetes Model (CDM), a non-product-specific, validated computer simulation model that projects the long-term outcomes related to interventions for type 2 diabetes, is used for simulation of these interventions. In the model, patients were treated initially on one of the three treatment options: liraglutide 1.2 mg daily, 1.8 mg daily, or sitagliptin 100 mg daily, each used as add-on therapy to metformin for 5 years. After 5 years all patients switched to basal insulin treatment for the remainder of the simulation (35-year time horizon overall). Incremental cost-effectiveness ratios (ICERs) were generated for liraglutide 1.2 mg compared with sitagliptin and liraglutide 1.8 mg compared with sitagliptin. Transition probabilities, health state utility values, and complication costs were obtained from published sources. All outcomes were discounted at 3% per annum, and the analysis was conducted from the perspective of a third-party payer in the US. Sensitivity analyses were performed to test robustness of the base case scenario. RESULTS: For liraglutide 1.8 mg vs sitagliptin, the ICER was $37,234 per QALY gained, while for liraglutide 1.2 mg vs sitagliptin, the ICER was $25,742 per QALY gained. In all sensitivity analyses, including setting the change in HbA1c to the lower limits of the 95% confidence intervals, the ICERs remained below US$ 50,000/QALY, a commonly accepted threshold in the US, except for the shortest time horizon of 10 years. CONCLUSIONS: The availability of liraglutide 1.2 mg and 1.8 mg with improved efficacy profiles over sitagliptin could improve patient care, with the incremental cost effectiveness ratio below $50,000 per QALY gained as add-on to metformin.