Tuberculosis decline in populations affected by HIV: a retrospective study of 12 countries in the WHO African Region.

Christopher Dye,Brian G Williams

doi:10.2471/blt.18.228577

Abstract

ObjectiveTo investigate which of the World Health Organization recommended methods for tuberculosis control have had the greatest effect on case incidence in 12 countries in the World Health Organization (WHO) African Region that carry high burdens of tuberculosis linked to human immunodeficiency virus (HIV) infection.MethodsWe obtained epidemiological surveillance, survey and treatment data on HIV and tuberculosis for the years 2003 to 2016. We used statistical models to examine the effects of antiretroviral therapy (ART) and isoniazid preventive therapy in reducing the incidence of tuberculosis among people living with HIV. We also investigated the role of tuberculosis case detection and treatment in preventing Mycobacterium tuberculosis transmission and consequently reducing tuberculosis incidence.FindingsBetween 2003 and 2016, ART provision was associated with the decline of tuberculosis in each country, and with differences in tuberculosis decline between countries. Inferring that ART was a cause of tuberculosis decline, ART prevented 1.88 million (95% confidence interval, CI: 1.65 to 2.11) tuberculosis cases in people living with HIV, or 15.7% (95% CI: 13.8 to 17.6) of the 11.96 million HIV-positive tuberculosis cases expected. Population coverage of isoniazid preventive therapy was too low (average 1.0% of persons eligible) to have a major effect on tuberculosis decline, and improvements in tuberculosis detection and treatment were either weakly associated or not significantly associated with tuberculosis decline.ConclusionART provision is associated with tuberculosis decline in these 12 countries. ART should remain central to tuberculosis control where rates of tuberculosis–HIV coinfection are high, but renewed efforts to treat tuberculosis are needed.

Highlights

Among people with latent Mycobacterium tuberculosis infection, coinfection with the human immunodeficiency virus (HIV) carries a 10- to 15-fold risk of developing active tuberculosis.[1,2,3] From 2003 to 2016, the countries worst-affected by the HIV epidemic, including Botswana, Eswatini and Lesotho reported national adult (15–49 years) HIV prevalence of over 20% and exceptionally high national tuberculosis incidence rates above 500 per 100 000 population per year (Table 1).[6]
Our analysis suggests that the rollout of antiretroviral therapy (ART), supported by the services needed to provide treatment, such as HIV testing, drug procurement, treatment supervision, outcome monitoring and nutritional supplements, has played a major part in the tuberculosis decline in southern and eastern Africa since 2003
Our results are broadly in line with a previous study[24] that found an association between ART coverage and the reduction in tuberculosis incidence among people living with HIV

Summary

Introduction

Among people with latent Mycobacterium tuberculosis infection, coinfection with the human immunodeficiency virus (HIV) carries a 10- to 15-fold risk of developing active tuberculosis.[1,2,3] From 2003 to 2016, the countries worst-affected by the HIV epidemic, including Botswana, Eswatini and Lesotho reported national adult (15–49 years) HIV prevalence of over 20% and exceptionally high national tuberculosis incidence rates above 500 per 100 000 population per year (Table 1).[6]. To reduce the incidence of tuberculosis in populations with a high proportion of M. tuberculosis and HIV coinfection, the World Health Organization (WHO) and the Joint United Nations Programme on HIV/AIDS (UNAIDS) primarily recommend drug treatments such as isoniazid preventive therapy and antiretroviral therapy (ART) to prevent progression from latent to active tuberculosis. Isoniazid preventive therapy, when used continuously with ART, generally gives coinfected adults additional protection from tuberculosis.[7,8,9,10] WHO and UNAIDS recommend combinations of drugs to prevent onward transmission of infection from patients with active tuberculosis.[6,11] Combination chemotherapy and ART are the two principal interventions used to reduce tuberculosis incidence and have the greatest population coverage and longest history of use. The efficacy of all these treatments has been demonstrated in experimental and observational studies[7,8,9,12,13,14] and drug treatments have the potential markedly to reduce incidence if high rates of treatment coverage can be achieved in target populations.[1,2,15,16,17]

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Results

Conclusion