Intensive lifestyle changes or metformin in patients with impaired glucose tolerance: Modeling the long-term health economic implications of the diabetes prevention program in Australia, France, Germany, Switzerland, and the United Kingdom
BACKGROUND:In the Diabetes Prevention Program (DPP), interventions with metformin (plus standard lifestyle advice) or intensive lifestyle changes (ILC) reduced the risk of developing type 2 diabetes mellitus (DM) by 31% and 58%, respectively, versus control (standard lifestyle advice only) in patients with impaired glucose tolerance (IGT). OBJECTIVE:The goal of this study was to establish whether implementing the active treatments used in the DPP would be cost-effective in Australia, France, Germany, Switzerland, and the United Kingdom. METHODS:A Markov model simulated 3 states-IGT, type 2 DM, and deceased-using probabilities from the DPP and published data. Country-specific direct costs were used throughout. RESULTS:Assuming only within-trial effects and costs of interventions, both metformin and ILC improved life expectancy versus control. Mean improvements in nondiscounted life expectancy were 0.11 and 0.22 years for metformin and ILC, respectively. Both interventions were associated with cost savings versus control in all countries except the United Kingdom, where a small increase in costs was observed in both intervention arms. When a lifetime effect of interventions was assumed, incremental improvements in life expectancy were 0.35 and 0.90 years for metformin and ILC, respectively. Results were sensitive to probabilities of developing type 2 DM, the projected long-term duration of effect of interventions after the 3-year trial period, the relative risk of mortality for type 2 DM compared with IGT, and the costs of implementing the interventions. CONCLUSIONS:Based on probabilities from the DPP and published data, in this model analysis, incorporation of the DPP interventions into clinical practice in 5 developed countries was projected to lead to an increase in DM-free years of life, improvements in life expectancy, and either cost savings or minor increases in costs compared with standard lifestyle advice in a population with IGT. Thus, financial constraints should not prevent the implementation of DM prevention programs.