Impact and cost-effectiveness of culture for diagnosis of tuberculosis in HIV-infected Brazilian adults.
BACKGROUND
Culture of Mycobacterium tuberculosis currently represents the closest "gold standard" for diagnosis of tuberculosis (TB), but operational data are scant on the impact and cost-effectiveness of TB culture for human immunodeficiency (HIV-) infected individuals in resource-limited settings.


RESULTS
We recorded costs, laboratory results, and dates of initiating TB therapy in a centralized TB culture program for HIV-infected patients in Rio de Janeiro, Brazil, constructing a decision-analysis model to estimate the incremental cost-effectiveness of TB culture from the perspective of a public-sector TB control program. Of 217 TB suspects presenting between January 2006 and March 2008, 33 (15%) had culture-confirmed active tuberculosis; 23 (70%) were smear-negative. Among smear-negative, culture-positive patients, 6 (26%) began TB therapy before culture results were available, 11 (48%) began TB therapy after culture result availability, and 6 (26%) did not begin TB therapy within 180 days of presentation. The cost per negative culture was US$17.52 (solid media)-$23.50 (liquid media). Per 1,000 TB suspects and compared with smear alone, TB culture with solid media would avert an estimated eight TB deaths (95% simulation interval [SI]: 4, 15) and 37 disability-adjusted life years (DALYs) (95% SI: 13, 76), at a cost of $36 (95% SI: $25, $50) per TB suspect or $962 (95% SI: $469, $2642) per DALY averted. Replacing solid media with automated liquid culture would avert one further death (95% SI: -1, 4) and eight DALYs (95% SI: -4, 23) at $2751 per DALY (95% SI: $680, dominated). The cost-effectiveness of TB culture was more sensitive to characteristics of the existing TB diagnostic system than to the accuracy or cost of TB culture.


CONCLUSIONS
TB culture is potentially effective and cost-effective for HIV-positive patients in resource-constrained settings. Reliable transmission of culture results to patients and integration with existing systems are essential.
Dowdy
David W
DW
Center for Tuberculosis Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
Lourenço
Maria C
MC
Cavalcante
Solange C
SC
Saraceni
Valeria
V
King
Bonnie
B
Golub
Jonathan E
JE
Bishai
David
D
Durovni
Betina
B
Chaisson
Richard E
RE
Dorman
Susan E
SE
D017088:AIDS-Related Opportunistic Infections / Q000175:diagnosis*; D001431:Bacteriological Techniques / Q000191:economics*; D001938:Brazil; D003362:Cost-Benefit Analysis; D015658:HIV Infections / Q000150:complications*; D006801:Humans; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D014376:Tuberculosis / Q000175:diagnosis*