OBJECTIVES: The NICE study was a five-year, open-label, randomized controlled trial that compared cardiovascular outcomes in Japanese type 2 diabetes patients intensively treated with human insulin (HI) or insulin aspart (IAsp). Using data from the NICE study, the cost-effectiveness of IAsp versus HI was evaluated from the perspective of a third-party healthcare payer over a ten-year time horizon (five years within-trial observation and five years post-trial extrapolation). METHODS: A discrete event simulation model was developed in Microsoft Excel® to assess the within-trial cost-effectiveness and make longer-term clinical projections in patients treated with regular human insulin or insulin aspart. Life expectancy, quality-adjusted life expectancy, cardiovascular event rates and costs were evaluated over a ten-year time horizon. Event costs were calculated from hospital receipt data supplied by the Japanese Medical Data Center. Annual insulin costs were obtained from the NICE study. Other pharmacy costs were assumed to be the same in both treatment arms and were not captured in the analysis. All costs were expressed in 2008 Japanese Yen (JPY) and future costs and clinical benefits were discounted at 3% annually. Sensitivity analyses were performed. RESULTS: Compared with HI, IAsp was dominant (life- and cost-saving) over a ten-year time horizon. IAsp was associated with an improvement in discounted life expectancy of 0.056 years and an improvement of 0.085 quality-adjusted life years (QALYs) versus HI. Insulin aspart was projected to save an average of JPY 290,719 per patient. As in the exclusively in-trial analysis, pharmacy costs were found to be higher (difference JPY 129,408), but were again more than offset by cost savings resulting from a reduced incidence of cardiovascular complications, a difference of JPY -420,126. CONCLUSIONS: In a Japanese type 2 diabetes population, prescribing rapid-acting insulin aspart significantly reduced cardiovascular complications, resulting in increased quality of life and decreased costs compared with human insulin.