Background: Isoniazid prophylaxis for 12 months effectively prevents tuberculosis in HIV-infected persons and may decrease the incidence of other HIV-related disease and mortality. Recent clinical trials have found that some short-course regimens also effectively prevent tuberculosis.
Objective: To compare the benefits, risks, and cost-effectiveness of isoniazid prophylaxis and short-course prophylaxis regimens.
Design: Decision and cost-effectiveness analysis.
Setting: United States.
Patients: Hypothetical patients who are HIV-infected and have CD4 counts of 200 cells/mm3 or less and positive results on tuberculin skin tests.
Interventions: Isoniazid prophylaxis lasting 12 months and six short-course prophylaxis regimens of isoniazid, rifampin, and pyrazinamide alone or in combination.
Measurements: 5-year survival rate, life expectancy, life-time incidence of tuberculosis, and cost per quality-adjusted life-year saved.
Results: Compared with no prophylaxis, the 12-month isoniazid regimen increased 5-year survival rates by 9% and life expectancy by 8.7 months, decreased incidence of tuberculosis by 27%, and saved 4 medical care dollars for every 1 spent on prophylaxis. Regimens of isoniazid for 6 months, isoniazid and rifampin for 3 months, and rifampin and pyrazinamide for 2 months had similar results: 6.2- to 8.6-month increases in life expectancy, 19% to 26% reductions in incidence of tuberculosis, and 1 to 7 medical care dollars saved for every 1 spent on prophylaxis. A 3-month regimen of isoniazid, rifampin, and pyrazinamide resulted in fewer clinical benefits and was the only regimen tested that did not save medical care dollars.
Conclusions: Prophylaxis decreases the incidence of tuberculosis and increases life expectancy for HIV-infected patients. Some regimens save medical care dollars, and some short-course regimens have clinical and economic benefits similar to those of the 12-month isoniazid regimen. Short-course prophylaxis is a reasonable alternative to the 12-month isoniazid regimen.