Cost-effectiveness of azithromycin for preventing Mycobacterium avium complex infection in HIV-positive patients in the era of highly active antiretroviral therapy

We conducted a cost-effectiveness analysis to determine the clinical and ec onomic consequences of Mycobacterium avium complex (MAC) prophylaxis in HIV -infected patients in the era of highly active antiretroviral therapy (HAAR T) in a health care system with access unrestricted by financial barriers. The analysis was performed from a health care perspective and compared azit hromycin (1200 mg/week) with no prophylaxis over a period of 10 years based on data from the Swiss HIV Cohort Study (SHCS) and randomized controlled t rials. The main outcome measures were: expected survival; average health ca re costs; and cost-effectiveness in 1997 Swiss francs (pound 1 corresponds to about 2.3 CHF) per life-year saved. In patients with an initial CD4 coun t <50 cells/mm(3) and no AIDS, azithromycin increased expected survival by 4 months. In patients with AIDS, HAART durability had a major impact on exp ected survival and costs. Incremental survival increased from 2 to 4 months if we assumed a 10 year, instead of a 3 year, HAART effect. The cost-effec tiveness of azithromycin relative to no prophylaxis in patients without AID S was between 47,000 CHF (3-year HAART effect) and 60,000 CHF (10-year HAAR T effect) per life-year saved. The cost-effectiveness ratio increased to 11 8,000 CHF per life-year saved in patients with symptomatic AIDS. In conclus ion, in the era of HAART, MAC prophylaxis with azithromycin increases expec ted survival and reduces health care costs substantially. Starting MAC prop hylaxis in patients without AIDS is more effective and cost-effective than in patients with AIDS.