Dapagliflozin as add-on to Metformin; Network Meta-Analysis and Budget Impact Analysis

Abstract

Scope of this paper was to conduct a budget impact analysis (BIA) of the introduction of dapagliflozin as add-on therapy to metformin in the perspective of the Italian National Health Service (NHS). Clinical data were drawn from a recent network meta-analysis (NMA) which, based on a systematic literature review and Bayesian statistical approach, analysed RCTs enrolling subjects with type 2 diabetes inadequately controlled on metformin monotherapy. After 1 year, compared to dipeptidyl peptidase-4 (DPP-4) inhibitors, thiazolidinediones (TZDs) and sulphonylureas, dapagliflozin showed similar HbA1c control, with similar or reduced risk of hypoglycaemia and with the additional benefit of weight loss. Data from the NMA were included in the BIA which comprised estimates of number of patients treated as well as the costs of drugs, of hypoglycaemia stripes, of severe hypoglycaemic and cardiovascular events. Unitary costs of resources were retrieved from local published sources and tariff lists. Sensitivity analyses were performed to test the robustness of the model. The BIA model results show a potential reduction of the NHS' budget for patients treated with drugs in add-on to metformin in the size of 2.3 to 1.6 Million Euros in the 3 years following launch of dapagliflozin. This level of saving was maintained even when sensitivity analyses were performed to exclude the costs of diabetes self-monitoring and of severe hypoglycaemias. Dapagliflozin can represent a convenient therapeutic option for the Italian NHS, as an add-on therapy, in the treatment of type 2 diabetes patients who failed control with metformin alone.