Preventive medicine for HIV-infected patients - An analysis of isoniazid prophylaxis for tuberculin reactors and for anergic patients

Objective:To analyze the policies of isoniazid prophylaxis for human immunodeficiency virus (HIV)-infected tuberculin reactors and for HIV-infected anergic patients with unknown tuberculin status. Methods:Transition-state model of clinical immune deterioration of HIV-infection over ten years, review of published data, and a survey of AIDS experts. Outcome measures are the numbers of tuberculosis cases and deaths prevented and isoniazid toxicity cases and deaths occurring with prophylaxis. Patients:Hypothetical cohorts of HIV-infected 40-year-olds. Results:Because the tuberculosis activation rate is so high in HIV-infected patients, the benefits of prophylaxis far outweigh the risks of isoniazid toxicity for tuberculin reactors with HIV infection at any stage of immune function: 1,469-2,868 tuberculosis cases and 170-274 deaths are prevented per 10,000 cohort over ten years, depending upon the cohort's initial immune state. The benefits of prophylaxis outweigh the risks of isoniazid toxicity for anergic HIV-infected patients if they come from a community with a 2% to 3% or greater prevalence of Mycobacterium tuberculosis infection. Conclusions:Isoniazid prophylaxis is a reasonable prevention measure for HIV-infected tuberculin reactors and for many HIV-infected anergic patients.