Cost-effectiveness and budget impact of obesity surgery in patients with type-2 diabetes in three European countries.

BACKGROUND: We aimed to establish a payer-perspective cost-effectiveness and budget impact (BI) model of adjustable gastric banding (AGB) and gastric bypass (GBP) vs conventional treatment (CT) in patients with BMI > or =35 kg/m(2) and type-2 diabetes T2DM, in Germany, UK and France. METHODS: Clinical evidence was obtained from literature and patient-reported EQ-5D scores given BMI and T2DM status from HODaR. Resource utilization data in AGB, GBP and CT were obtained from quoted publications so as to reflect practice in 2005. CT in each country was based on descriptions in HTA reports or based on co-authors' experience of current practice. Unit costs were obtained from published sources when available, or from co-authors' institutions. A deterministic algorithm with cost and utility discounting, enabled selection of inputs independently throughout the time scope for each of the 3 treatments, and included mean BMI, amounts of resources and unit costs. RESULTS: The base case time-scope was 5 years, and the annual discount rate for utilities and costs was 3.5%. Compared to CT, GBP yielded +80.8 kg/m(2).years, +2.6 T2DM-free-years and +1.34 QALYs. AGB yielded +57.8 kg/m(2).years, +2.5 T2DM-free-years and +1.03 QALYs. In Germany and France, both GBP and AGB yielded a cost decrease, and were thus dominant in terms of ICER compared to CT. In the UK, GBP and AGB yielded a cost increase, but were cost-effective. CONCLUSION: In patients with T2DM and BMI > or =35 kg/m(2), AGB and GBP are effective at 5-year follow-up in cost-saving in Germany and France, and are cost-effective in the UK with a moderate BI vs CT.