Analytical approach:
There were no data for infliximab in the treatment of acute exacerbations of ulcerative colitis. This study used a state-transition decision-analytic model to estimate the clinical and economic outcomes of each of the four treatment options, by combining data from a range of sources. The main time horizon was one year, with additional analyses conducted for periods of up to 10 years. The perspective was that of the UK National Health Service (NHS).
Effectiveness data:
Published clinical trials were used to derive the relative risk of colectomy with the treatment alternatives. The effectiveness data were from a network meta-analysis and a number of published studies. The data on surgical complication rates were from the UK inflammatory bowel disease audit. The data used to develop the treatment pathways was based on clinical trial evidence and UK clinical expert opinion. The main clinical parameters were the number of colectomies, the symptom-free remission after treatment, and the complications after surgery.
Monetary benefit and utility valuations:
The utility estimates were from a published study (Woehl, et al. 2007, see 'Other Publications of Related Interest' below for bibliographic details) that used the European Quality of life (EQ-5D) questionnaire weights, based on time trade-off methods.
Measure of benefit:
The measure of benefit was quality-adjusted life-years (QALYs) gained.
Cost data:
The direct costs included drug acquisition and administration, surgery and surgical complications, consultant follow-up visits, and diagnostic procedures. The unit costs of drugs were reported and were from the British National Formulary and the administration costs were from the Department of Health's national cost schedule. The resource use for hospitalisations and other procedures were from a Delphi panel of five experts. The currency was UK pounds sterling (£), the price year was 2006 to 2007, and future costs were discounted at a rate of 3.5% per year.
Analysis of uncertainty:
Multiple one-way sensitivity analyses were performed on the key parameters, including the drug effectiveness, time horizon, utility estimates, administration costs, failure rates, and lengths of hospitalisation. Probabilistic sensitivity analysis was also performed. The results of the uncertainty analysis were presented in a cost-effectiveness acceptability curve and a scattergram.