Background: Pioglitazone has been approved in Europe for oral combination therapy for type 2 diabetes mellitus. Along with other agents of the thiazolidinedione class, it has a novel intracellular mechanism of action. Clinical trials with pioglitazone have confirmed a strong product profile in terms of control of blood glucose and lipids. However, the drug acquisition cost for pioglitazone is greater than standard medications for type 2 diabetes. Long-term data regarding the cost effectiveness of pioglitazone-based combination therapy are not available.
Objective: To evaluate, using a decision analysis model, the cost effectiveness of pioglitazone-based combination therapy compared with relevant alternative medications for the treatment of type 2 diabetes in Germany.
Methods: This study compared the clinical effects and costs of pioglitazone 30 mg added to metformin in patients who failed metformin monotherapy and pioglitazone added to a sulphonylurea in patients who failed sulphonylurea monotherapy, with the most relevant treatment alternatives. A published and validated Markov model was adapted to reflect the management of type 2 diabetes. This simulated the number of severe complications occurring and the mean life expectancy of a diabetic cohort, which was based on the overweight group of the UK Prospective Diabetes Study at year 6 of follow-up. Drug treatment costs, other costs for general management of type 2 diabetes and the costs of complications were combined to compute overall lifetime treatment costs from the perspective of the German statutory healthcare system in 2002.
Results: Combination therapy with pioglitazone/metformin was associated with a higher life expectancy (15.2 years) relative to sulphonylurea/metformin (14.9 years) or acarbose/metformin (14.7 years). Likewise, pioglitazone/sulphonylurea (15.5 years) was superior to metformin/sulphonylurea (14.9 years) and acarbose/sulphonylurea (14.8 years). Undiscounted incremental cost-effectiveness ratios in comparison to the next best strategy were euro20,002 per life-year gained (LYG) for pioglitazone/metformin versus sulphonylurea/metformin, and euro8707 per LYG for pioglitazone/sulphonylurea versus metformin/sulphonylurea. After discounting costs and life expectancy at 5% per year, the incremental cost-effectiveness ratio was euro47 636 per LYG for pioglitazone/metformin versus sulphonylurea/metformin, and euro19 745 per LYG for pioglitazone/sulphonylurea versus metformin/sulphonylurea.
Conclusions: In this model, with its underlying assumptions and data, combination therapy with pioglitazone increased life expectancy in overweight type 2 diabetes patients at acceptable cost compared with other well established medications in Germany. These findings should be re-evaluated as soon as additional evidence becomes available from the currently ongoing long-term clinical and economic studies.