The geographical intersection of the HIV pandemic with the existing global tuberculosis (TB) epidemic has led to high rates of HIV-associated TB and related mortality over the past 25 years [1
]. During 2008, there were an estimated 1.4 million incident cases of HIV-associated TB worldwide, which accounted for 25% (0.5 million) of global deaths from HIV infection and AIDS [2
]. Sub-Saharan Africa bears the brunt of this epidemic, accounting for 4 of 5 cases of HIV-associated TB worldwide [2
]. TB incidence rates have increased 3–5-fold in many African countries with a high prevalence of HIV infection, and in the worst affected countries of South Africa and Swaziland, ~1% of the national population develops TB each year [2
]. The region with the second highest burden is southern and Southeast Asia, with 13% of the global caseload.
Extraordinary progress has been made in scaling up access to antiretroviral therapy (ART) in low- and middle-income countries (reaching 5.3 million persons by the end of 2009) [3
]. A majority of these persons (3.9 million) were in sub-Saharan Africa. Scale-up of ART in settings with a high burden of TB is associated with a number of opportunities and challenges. ART is a crucial component of case management of HIV-associated TB [4
], reducing mortality risk by 64%–95% [5
] and halving recurrence rates [6
]. In addition, ART has an important role in the prevention of HIV-associated TB, reducing risk in treated cohorts by a mean of 67% (95% confidence interval [CI], 61%–73%) [7
]. Furthermore, aggressive ART scale-up could potentially play a key role in the control of this epidemic [8
However, high rates of TB also present many challenges for ART services: TB is a major cause of morbidity and mortality, concurrent TB treatment and ART is complex [9
], and TB is associated with a substantial risk of nosocomial transmission [11
]. These challenges are amplified greatly by the major difficulties of screening and diagnosing TB in this group of patients. This may, in part, explain why only 4.1% of patients living with HIV infection worldwide were estimated to have been screened for TB during 2008 [2
In this article, we describe the burden and impact of TB on adults accessing ART programs in resource-constrained settings. We highlight the importance of effective TB screening and reliable diagnosis and review the range of conventional and novel TB diagnostic tools available for use in this context. A majority of the data reported are from sub-Saharan Africa. However, the principles outlined are relevant to other resource-constrained settings.