A Markov model, with a one-week cycle length, was developed to assess the cost effectiveness of the interventions. The time horizon was 52 weeks and the authors reported that the perspective of the Italian National Health Service was adopted.
Most of the effectiveness data were from a published study - the Inhaled Combination Asthma Treatment versus Seretide (ICAT-SE) study (Papi, et al. 2007, see 'Other Publications of Related Interest' below for bibliographic details). The ICAT-SE study was a phase III, multinational, multicentre, double-blind, randomised, two-arm parallel-group study. The primary outcome measure was successful asthma control, which was from the original data, from the ICAT-SE study.
Monetary benefit and utility valuations:
The utility values were from published studies, and the mean of the reported values was used in the model.
Measure of benefit:
The summary measures of benefit were the weeks lived with successfully controlled asthma, and quality-adjusted life-weeks or quality-adjusted life-years (QALYs).
The analysis considered asthma treatment costs including drugs, general practitioner (GP) visits, hospital admissions, specialist visits, blood tests and diagnostic tests. The drug dosages were from the ICAT-SE study, while other resource use was estimated, based on interviews with a panel of experts, including one GP and four lung specialists. The drug unit costs were based on their retail prices, while the health care unit costs were based on the Italian fees for health care services. All costs were reported in Euros (EUR).
Analysis of uncertainty:
The estimates and transition probabilities were varied in a univariate analysis. Monte Carlo simulation was used to examine the uncertainty in the model inputs and its impact on the results. These results were displayed on cost-effectiveness isocontour graphs.