The analysis was based on a Markov model with a two-year time horizon. The authors stated that the perspective of the UK National Health Service (NHS) was used.
The key clinical data on the treatment effect and tolerability came from the joint analysis of two pivotal double-blind, randomised controlled trials (RCTs) with similar designs and interventions. These included 1,326 patients, with 703 patients from one trial and 623 from the other. There were 646 patients in the quetiapine group and 680 patients in the placebo group. The length of follow-up was two years. The key clinical endpoint was the rate of recurrence of a mood event (either depressive or manic). Other data for the model were derived from published literature, the details of which were not given, and supplemented with some assumptions.
Monetary benefit and utility valuations:
The utility values were derived from a published report, the details of which were not provided.
Measure of benefit:
The summary benefit measures were acute mood events, acute mood event-related hospitalisations, and quality-adjusted life-years (QALYs). These benefits were discounted at 3.5% per annum.
The economic analysis included the costs of drugs, laboratory monitoring, contacts with health care professionals for the management of bipolar I disorder, and hospitalisations. A breakdown of the cost items was provided. The costs and quantities came from appropriate sources, such as the official guidelines published by the British Psychological Society, and the Royal College of Psychiatrists, and the British National Formulary. All costs were in UK pounds sterling (£) and the price year was 2007. A 3.5% annual discount rate was applied.
Analysis of uncertainty:
A deterministic one-way sensitivity analysis was undertaken on several model inputs. The sources for the ranges of values were not reported. A probabilistic sensitivity analysis was carried out, in which the input parameters were varied simultaneously.