Tuberculosis screening in high human immunodeficiency virus prevalence settings: turning promise into reality [State of the art series. Active case finding/screening. Number 5 in the series]

Abstract

SUMMARYTwenty years of sky-high tuberculosis (TB) incidence rates and high TB mortality in high human immunodeficiency virus (HIV) prevalence countries have so far not been matched by the same magnitude or breadth of responses as seen in malaria or HIV programmes. Instead, recommendations have been narrowly focused on people presenting to health facilities for investigation of TB symptoms, or for HIV testing and care. However, despite the recent major investment and scale-up of TB and HIV services, undiagnosed TB remains highly prevalent at community level, implying that diagnosis of TB remains slow and incomplete. This maintains high transmission rates and exposes people living with HIV to high rates of morbidity and mortality.More intensive use of TB screening, with broader definitions of target populations, expanded indications for screening both inside and outside of health facilities, and appropriate selection of new diagnostic tools, offers the prospect of rapidly improving population-level control of TB. Diagnostic accuracy of suitable (high throughput) algorithms remains the major barrier to realising this goal.In the present study, we review the evidence available to guide expanded TB screening in HIVprevalent settings, ideally through combined TB-HIV interventions that provide screening for both TB and HIV, and maximise entry to HIV and TB care and prevention. Ideally, we would systematically test, treat and prevent TB and HIV comprehensively, offering both TB and HIV screening to all health facility attendees, TB households and all adults in the highest risk communities. However, we are still held back by inadequate diagnostics, financing and paucity of population-impact data. Relevant contemporary research showing the high need for potential gains, and pitfalls from expanded and intensified TB screening in high HIV prevalence settings are discussed in this review. In high human immunodeficiency virus (HIV) prevalence settings, population-level tuberculosis (TB) incidence increased in parallel with adult HIV prevalence in the 1990s and remains extremely high, with over 1% of adults diagnosed with TB each year in many Southern African towns. 1 Outbreaks of multi-and extensively drug-resistant TB (XDR-TB) have been generated in HIV care clinics, and then spread into general communities. 2,3 Autopsy studies show that TB is the single biggest killer of people living with HIV (PLHIV), being the cause in 32% to 45% of HIV-related deaths 4 and with a high proportion of fatal cases undiagnosed in life. 4,5 Of the estimated 430 000 TB-related deaths among PLHIV during 2011, 79% were in Africa. These stark facts demonstrate the urgent need to strengthen TB prevention and care services using all available approaches, including more ambitious TB screening strategies.TB screening is the first step in both anti-tuberculosis treatment and TB prevention pathways, and has an integral place in routine HIV care and infection control. Key potential entry points for TB screening are illustrated in Figure 1. TB screening c...

Tuberculosis and non‐tuberculous mycobacteria among HIV‐infected individuals in Ghana

“…A retrospective cohort study of PLHIV described TB as the major AIDS defining event, but reported a quite modest event rate of 4.4% in the cohort with a median follow‐up time of 30 months (IQR; 12–54) . A review of intensified TB‐screening in other low‐ and middle‐income countries found a prevalence of confirmed TB between 6.3% and 25.7% in populations attending HIV care; the highest rates were found among HIV‐positive patients starting ART in South Africa .…”

Noncommunicable Lung Disease in Sub-Saharan Africa. A Community-based Cross-Sectional Study of Adults in Urban Malawi

“…The association with HIV raises the possibility that undiagnosed pulmonary TB may be responsible for part of this presentation (22)(23)(24)(25)(26). However, cough was less prevalent among younger age groups in whom the TB incidence would be expected to be highest.…”

The prevalence of HIV among adults with pulmonary TB at a population level in Zambia

“…The diagnosis of TB remains a challenge especially in areas where access to health services is limited and in view of HIV-positivity being associated with a high rate of extra-pulmonary TB, which offers formidable diagnostic challenges on its own [5]. …”