Short-course prophylaxis against tuberculosis in HIV-infected persons. A decision and cost-effectiveness analysis.

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, lifetime 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.