OBJECTIVES: A fixed-effects (weighted average) meta-analysis of three clinical trials showed the short-term therapy benefits of treating type 1 diabetic patients (mean age 40.3 years, duration of diabetes 16.3 years, HbA1c 8.3%, BMI 25.2 kg.m-2) with insulin detemir (IDet) versus neutral protamine Hagedorn (NPH) insulin as the basal component of basal-bolus therapy when used in combination with either insulin aspart (IAsp) or human soluble insulin (HSI). METHODS: A published validated diabetes model was used to estimate the long-term cumulative incidence of complications, life expectancy (LE), quality-adjusted life expectancy (QALE) and lifetime costs for IDet versus NPH regimens. The short-term treatment effects (0.13% points lower HbA1c, a 4% decrease in hypoglycaemic events and lower body mass index 0.21 kg.m-2) observed in the meta-analyses were projected using progression data derived from landmark clinical and epidemiological studies. The costs of treating complications in the German setting were taken from published sources and total direct costs (complications + treatment costs) for each arm were projected over patient lifetimes. Both costs and clinical outcomes were discounted at 5% annually. RESULTS: The IDet arm was associated with an increase in life expectancy, compared to NPH, of 0.052 years (12.270±0.130 versus 12.218±0.121 years) with a resulting gain in QALE of 0.144 quality-adjusted life years (QALYs) (6.23±0.07 versus 6.09±0.06 QALYs) due to a reduction in diabetes-related complications. Increased treatment costs for IDet resulted in greater total lifetime costs per patient than with NPH (€ 91,960±2333 versus € 89,367±2183, difference €2,593), leading to an incremental cost-effectiveness ratio of €18,070 per QALY gained. CONCLUSION: Short-term improvements seen with IDet versus NPH in basal-bolus therapy were projected to show improvements in both life expectancy and quality-adjusted life expectancy with a cost-effectiveness ratio which fell well within the range usually considered to represent value for money (