The analysis was based on a Markov model with a 17-week time horizon. The authors stated that a societal perspective was adopted.
The bulk of the clinical evidence came from a published pivotal, multicentre, prospective, randomised controlled trial. The remaining evidence was from published literature and the methods of these studies were not reported. The key assumption of the model was the equal success rate (100%) in both treatment arms, which was based on the trial results.
Monetary benefit and utility valuations:
The utility values were derived from Short Form (SF-36) Health Survey data collected in the pivotal trial. These data were converted to utilities using the SF-6D method.
Measure of benefit:
Quality-adjusted life-years (QALYs) were the summary benefit measure.
The economic analysis included the costs of radioiodine ablation, whole-body scan, in-patient stay, visits to a specialist and a general practitioner, TSH measurement, serum thyroglobulin count, thyroglobulin antibody test, productivity losses, and drugs. The costs were from Canadian sources, such as the Ontario Health Insurance Plan and the Ontario Drug Benefit formulary. A survey of 24 clinicians, treating 1,884 patients in Canada, was undertaken to estimate some of the resource use data. Other data were derived from published studies. The value of productivity lost was estimated from the average Canadian wage, using a friction cost method. All costs were in Canadian dollars (CAD) and referred to 2007 or 2008 prices.
Analysis of uncertainty:
One- and two-way sensitivity analyses were carried out to establish whether the base case findings were robust and to identify the most influential model inputs. Published ranges of values appear to have been used for most inputs. In an alternative scenario, it was assumed that radioiodine ablation was administered to out-patients.