Cost-Utility Analysis of Dapagliflozin Versus Saxagliptin Treatment as Monotherapy or Combination Therapy as Add-on to Metformin for Treating Type 2 Diabetes Mellitus

To assess the long-term cost effectiveness of dapagliflozin (DAPA) and saxagliptin (SAXA) separately or together in patients with type 2 diabetes mellitus (T2DM) inadequately controlled by metformin (MET). Five head-to-head randomised controlled trials of the efficacy of DAPA and SAXA in type 2 diabetes mellitus (T2DM) patients were found by searching PubMed, Embase and Cochrane from inception to October 2019. The lifetime disease progression and long-term effectiveness of therapy in patients were projected by the United Kingdom Prospective Diabetes Study Outcome Model 2 (UKPDS OM2) in three T2DM therapeutic groups: DAPA + SAXA, DAPA and SAXA. Each group used DAPA and/or SAXA as an add-on therapy to MET. The study took the perspective of Chinese healthcare service providers. Univariate, scenario and probabilistic sensitivity analyses were performed. The quality-adjusted life-years (QALYs) value of the DAPA + SAXA, SAXA and DAPA groups were 11.28, 11.26 and 11.45 years, respectively. The total costs were US$27,954.84, US$23,254.46 and US$25,608.49, respectively. DAPA was dominant over DAPA + SAXA. The DAPA + SAXA group presented an estimated QALY gain of 0.02 and a total cost increase of US$4700.39 over the SAXA group, with an incremental cost of US$217,530.10 per QALY. Compared with the SAXA group, the DAPA group had a QALY gain of 0.19 years and a total cost increase of US$2354.04, for an incremental cost of US$12,191.97 per QALY. The pharmacoeconomic results were robust to univariate, scenario and probabilistic sensitivity analyses. Compared with DAPA + SAXA or SAXA, DAPA appears to be a cost-effective therapy as add-on to MET for Chinese patients whose T2DM is insufficiently controlled by MET.