Analytical approach:
The analysis was based on a Markov model with a lifetime horizon (20 years). The authors stated that the perspective of the UK NHS was adopted.
Effectiveness data:
Some of the clinical data on survival associated with iron chelation therapy, both with desferrioxamine and deferasirox, were from a large observational study (n=165 regularly transfused patients). The risk of disease progression was from the retrospective analysis of 178 patients at a large Canadian hospital. Additional data were from published studies. A key assumption of the model was that the clinical outcomes (efficacy and compliance) were the same between treatment arms. This was assumed because there were no head-to-head studies between desferrioxamine and deferasirox. The impact of treatment-related complications was a key input for the model.
Monetary benefit and utility valuations:
The utility values were derived from a published study that used a time trade-off method, with a sample of the UK general public, to elicit the utilities for iron chelation therapy provided orally once daily or as a slow subcutaneous infusion. The utility decrements associated with therapy complications were from the Beaver Dam Health Outcomes study (a longitudinal study of health-related quality of life in a random sample cohort of 1,356 US adults). The utility decrements for acute myeloid leukaemia were from a published study that used the Health Utilities Index 2.
Measure of benefit:
Quality-adjusted life-years (QALYs) were the summary benefit measure and were discounted at an annual rate of 3.5%. Survival and iron chelation therapy complications were reported.
Cost data:
The economic analysis included the drug costs (acquisition and administration), monitoring (blood tests), and treatment of acute myeloid leukaemia, complications, and blood transfusions. The drug costs were from the British National Formulary. The cost of the administration of desferrioxamine was from a published economic evaluation. The costs of acute myeloid leukaemia were from a US study and included treatment, hospitalisation, blood transfusion, and other related medical costs. Other costs were from official price lists, NHS reference costs, and published studies. Most of the resource quantities were based on published studies. All costs were in UK pounds sterling (£) and were discounted at an annual rate of 3.5%.
Analysis of uncertainty:
One-way sensitivity analyses were carried out on those inputs affecting the drug-related costs, such as patient weight, average daily dose, days per week of treatment with desferrioxamine, and desferrioxamine administration costs. The proportion of desferrioxamine patients who used a balloon infuser or a battery-operated pump for the subcutaneous infusion was varied. The utility values, compliance rates, and monitoring costs were analysed.