Brazil: Isoniazid prevention of HIV-associated tuberculosis

In many high-income countries, isoniazid preventive therapy has formed the cornerstone of tuberculosis prevention for nearly 50 years. Isoniazid is also effective in low-income and middle-income countries with a high tuberculosis burden, although widespread implementation has been slow. In The Lancet Infectious Diseases, Betina Durovni and colleagues (1) present a large pragmatic before-and-after assessment of a policy to increase tuberculosis screening and the use of isoniazid preventive therapy to reduce the incidence of HIV-associated tuberculosis (HIV/TB) in Rio de Janeiro, Brazil. The ambitious stepwise intervention was multipronged and delivered across the city's health service. Primary analyses did not show an overall reduction in tuberculosis incidence, although there was a small reduction in the combined outcome of tuberculosis and all-cause mortality. Adjusted for clinical characteristics, the intervention had a modest effect on outcomes. Effect sizes varied by adherence to clinical follow-up, and were greatest in the group of patients who remained in care.