Abstract
BackgroundTuberculosis is one of the most prominent health problems in the world, causing 1.75 million deaths each year. Rapid clinical diagnosis is important in patients who have co-morbidities such as Human Immunodeficiency Virus (HIV) infection. Direct microscopy has low sensitivity and culture takes 3 to 6 weeks [1-3]. Therefore, new tools for TB diagnosis are necessary, especially in health settings with a high prevalence of HIV/TB co-infection.MethodsIn a public reference TB/HIV hospital in Brazil, we compared the cost-effectiveness of diagnostic strategies for diagnosis of pulmonary TB: Acid fast bacilli smear microscopy by Ziehl-Neelsen staining (AFB smear) plus culture and AFB smear plus colorimetric test (PCR dot-blot).From May 2003 to May 2004, sputum was collected consecutively from PTB suspects attending the Parthenon Reference Hospital. Sputum samples were examined by AFB smear, culture, and PCR dot-blot. The gold standard was a positive culture combined with the definition of clinical PTB. Cost analysis included health services and patient costs.ResultsThe AFB smear plus PCR dot-blot require the lowest laboratory investment for equipment (US$ 20,000). The total screening costs are 3.8 times for AFB smear plus culture versus for AFB smear plus PCR dot blot costs (US$ 5,635,760 versus US$ 1,498, 660). Costs per correctly diagnosed case were US$ 50,773 and US$ 13,749 for AFB smear plus culture and AFB smear plus PCR dot-blot, respectively. AFB smear plus PCR dot-blot was more cost-effective than AFB smear plus culture, when the cost of treating all correctly diagnosed cases was considered. The cost of returning patients, which are not treated due to a negative result, to the health service, was higher in AFB smear plus culture than for AFB smear plus PCR dot-blot, US$ 374,778,045 and US$ 110,849,055, respectively.ConclusionAFB smear associated with PCR dot-blot associated has the potential to be a cost-effective tool in the fight against PTB for patients attended in the TB/HIV reference hospital.
Highlights
Tuberculosis is one of the most prominent health problems in the world, causing 1.75 million deaths each year
In a hospital setting with a high burden of TB and Human Immunodeficiency Virus (HIV), we investigated the cost-effectiveness of a home-made colorimetric polymerase chain reaction (PCR) (PCR dot-blot) to diagnose TB using expectorated sputum from patients suspected of having pulmonary tuberculosis (PTB), in parallel with direct microscopy by Ziehl-Neelsen staining for PTB diagnosis, using the combination of positive culture with the clinical definition of PTB as the gold standard
We found that the use of AFB smear plus PCR dot-blot was less cost-effective per case correctly diagnosed, than the cost-effectiveness described using the decision model for automated PCR (Roche Mycobacterium Tuberculosis Amplicor PCR system), probably due to the lower accuracy observed with in house PCR techniques [11,33]
Summary
Tuberculosis is one of the most prominent health problems in the world, causing 1.75 million deaths each year. Rapid clinical diagnosis is important in patients who have comorbidities such as Human Immunodeficiency Virus (HIV) infection. Tuberculosis is one of the most important health problems in the world, causing 1.75 million deaths each year, in 2007. Rapid clinical diagnosis is more challenging in patients who have co-morbidities, such as Human Immunodeficiency Virus (HIV) infection. Diagnostic testing for tuberculosis has remained unchanged for nearly a century, but newer technologies hold promise for a revolution in tuberculosis diagnostics. Tests such as the nucleic acid amplification assays allow more rapid and accurate diagnosis of pulmonary and extrapulmonary tuberculosis. New tools for TB diagnosis are necessary, especially in health settings with a high prevalence of HIV/TB co-infection
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