Analytical approach:
The analysis was based on a Markov model, with a lifetime horizon. The author stated that a societal perspective was adopted.
Effectiveness data:
A search of the literature in the PubMed database was carried out to identify the relevant sources of evidence. The accuracy of the screening tests was a key input for the model and this was from meta-analyses of studies conducted in developed countries. Other sources included meta-analyses, Japanese life tables, and cohort studies of Japanese patients. The efficacy of treatment for tuberculosis was based on long-term cohort studies.
Monetary benefit and utility valuations:
The utility values were from a published study, identified by the literature search in PubMed.
Measure of benefit:
Quality-adjusted life-years (QALYs) were the summary benefit measure and were discounted at an annual rate of 3%.
Cost data:
The economic analysis included the costs of screening, six-months of isoniazid chemoprevention, the treatment of active tuberculosis, and productivity lost. The costs of a chest X-ray included the physician visit, and radiology technician's time. The cost of QFT included taking blood, the screening kit, physician visit, and laboratory technician's time. Most of these costs were from published literature. Productivity lost was estimated using data from the Japanese Ministry of Health, Labour, and Welfare. The price year was 2009. All costs were in US $ and were discounted at a rate of 3% per annum.
Analysis of uncertainty:
One-way sensitivity analyses were carried out on the model inputs. The ranges of values were based on published data. A first-order probabilistic sensitivity analysis was performed, using Monte Carlo simulation, and cost-effectiveness acceptability curves were created.