OBJECTIVES: To evaluate the clinical benefits of raising HDL-c by adding Niaspan® on coronary heart disease (CHD) endpoints in type 2 diabetes patients on statin therapy. METHODS: Two successive models were developed to project long-term clinical benefits of treating patients over different time periods. The first model (Monte Carlo simulation) was used to evaluate the impact of simvastatin treatment on lipid levels and identify patients with low HDL-c. Baseline cohort characteristics and effects of statin treatment were taken from the diabetic sub-population of the 4S study. In patients with HDL-c <1 mmol/L, treatment with statin plus add-on Niaspan® was compared to statin monotherapy. Niaspan® treatment effects were taken from several clinical trials as summarized in the European SPC. The second model was then used to simulate the development of CHD events based on the Framingham risk formulae. This Markov model included five states: no CHD, history of myocardial infarction (MI), history of MI and angina, and dead. Cycle length was one year. RESULTS: Addition of Niaspan® (2g daily) to statin treatment was associated with a lower cumulative incidence of CHD events than statin monotherapy. Absolute risk reductions of 2.1%, 4.0% and 8.1% for myocardial infarction, 0.5%, 0.9% and 1.3% for angina, and 1.0%, 1.9% and 4.0% for CHD death were projected at time horizons of 5, 10 and 35 years respectively. CONCLUSIONS: Due to its positive effect on HDL-c levels, addition of Niaspan® to statin treatment was projected to reduce the cumulative incidence of CHD events compared to statin monotherapy in type-2 diabetes patients with persistently low HDL-c. These data indicate that as the treatment period increases, the clinical benefits associated with statin plus Niaspan® may also increase compared to statin monotherapy.