Three quarters of people with HIV/TB co-infection did not receive Xpert MTB/RIF testing for TB diagnosis between 2012 and 2014, according to a survey of cohorts in 19 low- and middle-income countries by the International Epidemiologic Databases to Evaluate AIDS (IeDEA) Consortium, presented by Dr Kate Clouse at the 46th Union World Conference on Lung Health in Cape Town from 2 to 6 December.
Since 2011, the World Health Organization (WHO) has recommended Xpert MTB/RIF as the initial TB diagnostic test in individuals who may have multi-drug resistant TB or HIV-associated TB. Xpert MTB/RIF is a rapid test for identification of TB and rifampicin resistance. The test is being rolled out as a newer diagnostic for TB management in countries with a high burden of TB and HIV co-infection and has been shown to reduce treatment gaps and delays in treatment initiation in South Africa.
Reducing the time between identification of symptoms that suggest TB and the start of treatment is critically important. A long delay between seeking health care and starting treatment increases the risk of death from TB. People with TB may be lost from care and in the meantime pass on TB to their close contacts.
The retrospective survey used patient-level data on HIV and TB diagnosis and treatment, and outcomes were collected from an observational cohort of adults with HIV diagnosed with TB from 2012 to 2014, who were enrolled in the HIV care programme at an IeDEA site.
The countries included in the survey are Benin, Burundi, Cameroon, Côte d’Ivoire, Mali, Rwanda, the Democratic Republic of the Congo, Senegal, South Africa, Uganda, Philippines, Brazil, Honduras, Mexico and Peru, where one site was surveyed for each country. 20 sites were surveyed in Kenya, and two each in Tanzania, Thailand and Vietnam. All site-level data was completed once by the facility manager in mid-2012 and included data collected on the type of HIV and TB services provided by the facility or externally.
The median CD4 count was 115 cells/mm3 (IQR: 40 – 248 cells/mm3). 47% (n = 1255) were diagnosed with TB in 2012, 38% (n = 1044) in 2013 and 16.3% (n = 448) in 2014. 41% were female and 59% male and the median age was 35 years (IQR: 29 – 42).
The survey of 2747 people with TB/HIV co-infection found that 64.8% (n = 1780) of TB cases were not bacteriologically confirmed by Xpert MTB/RIF, smear microscopy, culture or other nucleic acid amplification test (NAAT) and treatment was started empirically.
The Xpert MTB/RIF tests had results documented for 4.8% (n = 133) of the cases surveyed, after 19.5% (n = 536) of the results were declared missing. 39.1% (n = 52) were negative for TB and 60.9% (n = 81) were diagnosed as positive for TB. 18.5 % (n = 15) of those were found to be resistant to rifampicin.
The survey found no association between documentation of Xpert MTB/RIF test and favourable (cured or completed treatment) TB outcome (RR = 1.02, 95% CI: 0.86 – 1.22), when adjusting for site and year of diagnosis using inverse probability weighting.
In the TB treatment outcome results, 1727 (62.9%) had been cured or completed treatment, while 615 (22.4%) had unfavourable outcomes, including treatment failure, default, death or unknown outcomes). 52 (1.9%) were still on therapy, 117 (4.3%) had been transferred and 236 (8.6%) had been lost to follow-up.
Limitations of the study included that data for HIV/TB cases could not be collected in all settings and the choice of cases was up to the local team at sites. There is also a potential for unmeasured confounders such as the timing or use of empiric TB therapy.
“Although the majority of sites had access to Xpert MTB/RIF, three-quarters of TB cases received no such test. Operational research must address global implementation challenges of Xpert MTB/RIF testing,” said Dr Clouse.
Clouse L et al. Low implementation of Xpert MTB/RIF among HIV - TB coinfected adults: a survey of 19 low/middle income countries from the IeDEA Consortium OA: 367-04. 46th Union World Conference on Lung Health, Cape Town, 2015