Antiretroviral therapy for tuberculosis control in nine African countries

Abstract

HIV has increased the incidence of tuberculosis (TB) by up to sevenfold in African countries, but antiretroviral therapy (ART) reduces the incidence of AIDS-related TB. We use a mathematical model to investigate the short-term and long-term impacts of ART on the incidence of TB, assuming that people are tested for HIV once a year, on average, and start ART at a fixed time after HIV seroconversion or at a fixed CD4 + cell count. We fit the model to trend data on HIV prevalence and TB incidence in nine countries in sub-Saharan Africa. If HIV-positive people start ART within 5 y of seroconversion, the incidence of AIDS-related TB in 2015 will be reduced by 48% (range: 37-55%). Long-term reductions depend sensitively on the delay to starting ART. If treatment is started 5, 2, or 1 y after HIV seroconversion, or as soon as people test positive, the incidence in 2050 will be reduced by 66% (range: 57-80%), 95% (range: 93-96%), 97.7% (range: 96.9-98.2%) and 98.4% (range: 97.8-98.9%), respectively. In the countries considered here, early ART could avert 0.71 ± 0.36 [95% confidence interval (CI)] million of 3.4 million cases of TB between 2010 and 2015 and 5.8 ± 2.9 (95% CI) million of 15 million cases between 2015 and 2050. As more countries provide ART at higher CD4 + cell counts, the impact on TB should be investigated to test the predictions of this model.Africa | HIV | test-and-treat

Ability of preventive therapy to cure latent Mycobacterium tuberculosis infection in HIV-infected individuals in high-burden settings

“…To minimize bias we included data from the entire trial period in the placebo arms but only data from the posttreatment period from the intervention arm(s). We account for potential differences in CD4 counts between arms by explicitly including a previously parameterized time-dependent model of decline in CD4 (11,12). This approach minimizes bias due to the differential risk of TB between the trial arms during the intervention period which could not be directly adjusted for, because we did not have access to the individual-level data.…”

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]

“…11,79 Irrespective of their final diagnosis, people identified as having symptoms of TB have a high probability of being HIV-infected, 22,80 being unaware of their HIV status, being eligible for ART 80 and having a high risk of death if their HIV is not promptly diagnosed and treated. [80][81][82][83] Indeed, in settings with generalised HIV epidemics, the NNTS to identify one patient with undiagnosed HIV is far lower than the NNTS to identify one patient with undiagnosed TB.More completely integrated TB-HIV interventions include HIV treatment-as-prevention (TasP) strategies providing home-based HTC with TB screening and immediate ART and IPT for HIV-positive individuals, 84 and combined TB and household-based HIV and TB prevention. 6 ART for TasP has extremely high potential as a TB control strategy, with declining national and regional TB incidence apparent already just from routine ART scaleup.…”

HIV, 95‐95‐95 and the allocative efficiency fallacy: why treating everyone makes sense from a humanitarian, clinical, economic and disease control perspective

“…Despite the problematic de‐prioritization of treatment, the models do conclude that increasing treatment coverage could lower incidence, a finding common among most models published over the past decade 7, 9, 10, 11, 12, 13, 14. However, in contrast to this finding, the Optima models allocate resources to “prevention” as equally or more important as providing access to treatment – ignoring the fact that treatment is the most powerful form of prevention.…”