OBJECTIVES: In a recent randomized, controlled clinical study in 447 patients with type 1 diabetes, use of insulin detemir (IDet) versus neutral protamine hagedorn (NPH) insulin in a basal (twice daily)/bolus regimen with insulin aspart (IAsp) as bolus insulin, demonstrated that IDet/IAsp was associated with a risk reduction of 22% for hypoglycemic events (p=0.029), a reduction of 0.2 kg in body weight (p<0.001) and decreased systolic blood pressure (SBP) (3 mmHg, p<0.001) versus NPH/IAsp over 6 months of treatment. No significant difference in HbA1c was noted. The aim of this analysis was to assess the impact of these changes over long-term treatment with IDet/IAsp versus NPH/IAsp. METHODS: A peer-reviewed, validated computer simulation model, was used to project these short-term findings to evaluate long-term clinical and cost outcomes. Transition probabilities and risk adjustments were derived from published studies. Baseline cohort characteristics were taken from the clinical trial. Total direct costs (complications+treatment costs) were derived from published sources and projected over patients' lifetimes from a German National Healthcare perspective. Costs and clinical benefits were discounted at 3.5% annually. RESULTS: Decreased incidence of hypoglycemic events, improved BMI and SBP associated with IDet/IAsp treatment led to fewer diabetes-related complications, increased life expectancy (0.15 years) and improved quality-adjusted life expectancy (0.22 QALYs) compared to NPH/IAsp. Mean total lifetime costs were €1,204 per patient higher in the IDet/IAsp treatment arm than in the NPH/IAsp group, leading to incremental cost-effectiveness ratios of €8,027 per LYG and €5,473 per QALY gained. CONCLUSIONS: Short-term clinical improvements associated with IDet/IAsp were projected to lead to a lower incidence of complications, improved life expectancy and quality-adjusted life expectancy compared to NPH/IAsp. Reductions in the cost of complications partially offset the costs of IDet/IAsp treatment, leading to incremental cost-effectiveness ratios within the range considered to represent good value for money.