Tuberculosis preventive therapy for HIV-infected people in sub-Saharan Africa is cost-effective

Since antiretroviral therapy is largely unavailable to HIV-infected patients in developing countries and recent clinical trials have shown that tuberculosis (TB) preventive therapy can reduce TB and HIV-associated morbidity and mortality, we studied the effectiveness and cost-effectiveness of TB preventive therapy for HIV-infected persons in sub-Saharan Africa.

A Markov model that used results of clinical trials of TB preventive therapy in sub-Saharan Africa and literature-derived medical care costs was used to evaluate three preventive therapy regimens in HIV-infected, tuberculin-positive patients in Uganda: (1) daily isoniazid (INH) for 6 months, (2) daily INH and rifampin (RIF) for 3 months, and (3) twice-weekly RIF and pyrazinamide (PZA) for 2 months.

All three regimens extend life expectancy and reduce the number of TB cases. When only medical care costs are considered, all three preventive therapy regimens cost more than not providing preventive therapy to extend life and prevent active tuberculosis. When medical care and social costs are considered together, 6-months of daily INH treatment will save money relative to no preventive therapy and when the costs associated with treating secondary infections are included, all three preventive therapy regimens are less expensive than no preventive therapy. With the inclusion of secondary infection costs, 6 months of daily INH results in savings of $24.16 per person.

TB preventive therapy taken by HIV-infected tuberculin reactors in sub-Saharan Africa results in extended life-expectancy, reduction of the incidence of TB and monetary savings in medical care and social costs. TB control policy in sub-Saharan Africa should include preventive therapy.