Analytical approach:
A compartmental model was used to simulate a cohort of individual patients of various ages, with active tuberculosis, over their lifetime. The authors stated that the analysis took the perspective of the health care taxpayer.
Effectiveness data:
The clinical data were mainly from the implementation of the Find and Treat service in London, UK, between September 2007 and September 2010. The analysis included 48 mobile screening unit cases, 188 cases referred for case management and 180 cases referred following loss to follow-up. The control group consisted of 252 age-matched patients, with risk factors, who passively presented and were notified to the Health Protection Agency between January, 2009 and August, 2010. The efficacy of the programme in identifying and treating tuberculosis cases was a key input for the model and these data were directly from the programme database. Other inputs were from published sources and guidelines.
Monetary benefit and utility valuations:
The utility values for untreated cases of tuberculosis and for improved health after two months of treatment were published estimates, obtained using the European Quality of life (EQ-5D) instrument.
Measure of benefit:
Quality-adjusted life-years (QALYs) were the summary benefit measure and they were discounted at an annual rate of 3.5%.
Cost data:
The economic analysis included the costs of staff salaries, training and development, travel and subsistence, administration, maintenance, cleaning, insurance, fuel, office management, and radiography, including equipment maintenance. Staff costs were increased to account for qualifications and capital overheads. The quantities of resources and costs for the programme were from the Find and Treat service budget. The cost of treatment for tuberculosis was estimated using National Institute for Health and Clinical Excellence (NICE) guidelines. The costs of diagnostic testing included the laboratory culture test, which was based on the official tariff for the microbiological pathology service. All costs were in UK pounds sterling (£) at 2009 to 2010 prices. A 3.5% annual discount rate was applied.
Analysis of uncertainty:
Alternative scenarios that were less favourable to the Find and Treat service were considered, including increased costs for mobile screening, increased costs for tuberculosis treatment, better quality of life with untreated tuberculosis, worse quality of life while on tuberculosis treatment, only half the asymptomatic cases progress to symptomatic disease, reduced loss to follow-up without the service for referred cases, and passive return to treatment for those referred due to loss to follow-up.