Cost Effectiveness of Saxagliptin and Metformin versus Sulfonylurea and Metformin in the Treatment of Type 2 Diabetes Mellitus in Germany

Abstract

The lack of adequate glycaemic control for patients with type 2 diabetes mellitus (T2DM), especially with existing second-line therapies, represents an unmet medical need. Of the newer therapies, the incretin-based medicines, such as saxagliptin, look promising to consolidate second-line pharmacotherapy. This study evaluates the long-term economic consequences of saxagliptin versus sulfonylurea (glipizide) as second-line therapy when used in combination with metformin after failure of monotherapy treatment with metformin, in patients with T2DM in Germany. A published discrete event simulation model with a fixed-time increment was used to model the effects of different treatment scenarios over a 40-year (life-) time horizon. Disease progression was modelled using evidence from the United Kingdom Prospective Diabetes Study (UKPDS) 68. The treatment sequence matched that of published German guidelines, and efficacy and safety data were derived from published sources. The model assumes that quality-adjusted life-years (QALYs) are affected by complications, hypoglycaemic events and weight change over a lifetime. Costs were specific to the German setting, where sulfonylureas are generic. Costs and effects were discounted annually at 3%. The extended perspective of the national sick funds was adopted, and recommendations from the Institute for Quality and Efficiency in Health Care (IQWiG) were considered. In the base-case analysis, treatment with saxagliptin plus metformin was associated with a lower incidence of both symptomatic and severe hypoglycaemic events, resulting in an incremental benefit of 0.12 QALYs and an incremental cost-effectiveness ratio (ICER) of €13,931 per QALY gained compared with sulfonylurea plus metformin (year of costing 2009). Modest reductions in all macro- and microvascular complications were seen in those receiving saxagliptin plus metformin compared with sulfonylurea plus metformin. Sensitivity analysis showed that treatment-related weight changes, as a risk factor for complications, represent the most influential driver of cost effectiveness. The study demonstrated improved outcomes with saxagliptin at a cost that would likely be considered acceptable in the German setting. Furthermore, the findings of the sensitivity analysis suggest that the results are robust to various assumptions concerning input variables and modelling assumptions.