Title: The Cost-Effectiveness of Dapagliflozin In Combination With Insulin for the Treatment of Type 2 Diabetes Mellitus (T2dm) In Spain
Abstract: To assess the cost-effectiveness of dapagliflozin, a sodium-glucose co-transporter-2 (SGLT-2) inhibitor versus dipeptidyl peptidase-4 inhibitor (DPP4i) both added on top of insulin, or compared to insulin alone (±oral anti-diabetes agents) for patients who are inadequately controlled on insulin strategy. The CARDIFF diabetes model was used. Clinical inputs were derived from a randomized clinical trial comparing dapagliflozin add-on to insulin with insulin alone, and network-meta-analysis for the comparison with DPP4i. Together with United Kingdom Prospective Diabetes Study (UKPDS) equations, the model predicts disease progression and the number of micro- and macro-vascular complications, along with diabetes-specific and all-cause mortality. The perspective of the Spanish health care payer was adopted over a lifetime horizon. Costs and utilities were assigned to the appropriate model parameters to calculate total Quality-Adjusted-Life-Years (QALYs) and total costs. Deterministic and probabilistic sensitivity analyses were conducted. Compared to insulin alone, dapagliflozin added to insulin was associated with 0.698 incremental QALYs (95%CI: 0.442; 1.211) at an additional cost of €1,508 (95%CI: €611; €1,517), resulting in an incremental cost-effectiveness ratio (ICER) point estimate of €2,159/QALY. Dapagliflozin was found to dominate DPP4i add-on to insulin, being associated with slightly less costs (-€51; 95%CI: -€913; €553) and higher QALYs (0.168; 95%CI: -0.007; 0.417). At a willingness-to-pay threshold of €20,000/QALY, the dapagliflozin strategy was estimated to have a 100% probability of being cost-effective when compared to the insulin alone, and a 98% probability when compared to the DPP4i strategy. These findings were shown to be robust to variation in range of model parameters. Dapagliflozin added on top of Insulin was predicted to be a cost-effective (vs. insulin alone) and cost saving (vs DPP4i) alternative in Spain in combination with insulin for patients who are inadequately controlled with insulin treatment regimens