Cost and clinical implications of diabetes prevention in an Australian setting: A long-term modeling analysis

Aims/hypothesis: Metformin and intensive lifestyle changes (ILC) reduced the incidence of type 2 diabetes (T2D) versus standard care (control) in overweight or obese subjects with impaired glucose tolerance (IGT) in the Diabetes Prevention Program (DPP) trial and Diabetes Prevention Program Outcomes Study (DPPOS). We projected lifetime clinical and economic outcomes based on the results from the DPP + DPPOS, from a 3rd-party payer perspective in Australia.

Methods: A semi-Markov, 2nd-order Monte Carlo model was developed with four health states: “normal glucose regulation” (NGR); IGT; T2D and ‘dead’. Outcomes were discounted at 5% annually. Univariate and probabilistic sensitivity analyses were performed. Incremental cost-effectiveness ratios (ICERs) were calculated.

Results: Cumulative incidence (standard deviation) of T2D was 89.7% (0.2), 83.8% (0.2) and 73.4% (0.3%) for control, metformin and ILC respectively. Lifetime incremental direct costs were $1217 (4411) per subject for metformin versus control, with cost savings of $289 (4296) for ILC versus control. ILC therefore dominated control, with improvements in clinical outcomes and overall cost savings. Incremental costs per QALY-gained for metformin versus control were $10,142. Probability of cost-effectiveness at willingness-to-pay threshold of $50,000 was 78% and 100% for metformin or ILC respectively. Results were most sensitive to probabilities of developing T2D and costs of implementing the interventions.

Conclusions/interpretation: Substantial improvements in lifetime clinical outcomes could be expected in high risk subjects treated with metformin or ILC. Prevention of T2D in this group of subjects is good value for money, and may even lead to long term cost savings.