Aims: To determine the cost-effectiveness of adding pioglitazone to existing treatment regimens in patients with Type 2 diabetes with a history of macrovascular disease who are at high risk of further cardiovascular events.
Methods: We conducted two analyses. A within-trial cost-effectiveness analysis (CEA) based on data from the PROspective pioglitAzone Clinical Trial In macroVascular Events (PROactive) Study was performed to estimate the impact of additional pioglitazone treatment on life expectancy, quality-adjusted life expectancy (QALE) and macrovascular events. PROactive data was then used as a basis for a lifetime modelling analysis using a modified version of the validated CORE diabetes model that simulated the same outcomes over a 35-year time horizon. We accounted for direct medical costs from a health-care payer perspective and related these to the clinical outcomes from the study. Costs and benefits were discounted at 3.5% per annum and extensive sensitivity analyses were performed to account for uncertainty in input parameters.
Results: (i) Within-trial CEA: compared with placebo, pioglitazone was associated with improved life expectancy (undiscounted 0.0109 years), increased QALE [0.0190 quality-adjusted life years (QALYs)] and slightly higher costs ( pounds 102 per patient). After a mean treatment period of 3 years, the incremental cost-effectiveness ratio (ICER) of pioglitazone vs. placebo was pounds 5396 per QALY gained. The ICERs were relatively insensitive to cost and utility values and were most sensitive to event rates in the pioglitazone arm. (ii) Long-term CEA: pioglitazone was associated with improvements in clinical outcomes based on model projections beyond the PROactive Study. Patients treated with pioglitazone could expect improved life expectancy (undiscounted 0.406 years), increased QALE (0.152 QALYs) and higher costs of care ( pounds 619 per patient) compared with those on existing treatment alone. The base case analysis indicated that the ICER of pioglitazone vs. placebo was pounds 4060 per QALY gained. The cost-effectiveness acceptability curve showed there was an 84.3% likelihood that pioglitazone would be considered cost-effective in the UK using a willingness-to-pay threshold of pounds 30 000 per QALY gained. These long-term results were most sensitive to variation in the time horizon, the duration of cardiovascular benefit of pioglitazone, and changes in mortality rates.
Conclusions: The addition of pioglitazone to existing therapy in patients with Type 2 diabetes at high risk of further cardiovascular events is cost-effective and represents good value for money by currently accepted standards in the UK.