This economic evaluation was based on a state transition model which simulated the costs and benefits of scanning plus treatment, versus no scanning and no treatment. The time horizon of the analysis was not clearly stated, but it appears to have been three years. The authors did not state explicitly the perspective adopted.
The clinical data were derived from known, relevant studies, which were selected by the authors. Japanese sources were used for epidemiological and demographic inputs. Similarly, the risk of fracture for women with osteoporosis came from a large Japanese study which involved 12,419 elderly women. The treatment effect for risedronate was based on meta-analysed data from large trials of Western women and this was the key clinical outcome.
Monetary benefit and utility valuations:
The utility valuations were derived from published sources using weighted means associated with specific health conditions. The authors stated that the utility weights came from Japanese women.
Measure of benefit:
Quality-adjusted life-years (QALYs) were used as the summary benefit measure and they were discounted at an annual rate of 5%.
The health services included drugs, BMD screening, bone resorption marker test, general practitioner consultations, and medical expenditures associated with fractures (inpatient and outpatient costs). These items were valued using national remuneration standards for health insurance services, and national health insurance drug price standards. The unit costs were presented separately from the quantities of resources used. All costs were in US dollars ($) and Japanese yen (JPY). The price year was not explicitly reported, but most of the sources for unit costs were dated 2002. A 5% annual discount rate was applied to future costs.
Analysis of uncertainty:
A deterministic, univariate, sensitivity analysis was carried out on selected model inputs which were varied by plus or minus 10% of their baseline values. Changes in the assumption for patient compliance were also made.