Prevention of disseminated Mycobacterium avium complex infection with reduced dose clarithromycin in patients with advanced HIV disease

Objective: To evaluate the ability of once daily reduced dose clarithromycin to prevent disseminated Mycobacterium avium complex (dMAC) infection in patients with advanced HIV disease. Design: Non-randomized, retrospective study. Setting: Outpatient clinic of an urban university-affiliated municipal hospital. Patients: A group of 192 HIV-infected patients with a CD4 count < 100 x 10⁶ cells/l who were followed for at least 90 days during a 6-year period (1991-1996) before the use of protease inhibitors. Interventions: Clarithromycin 500 mg orally once daily (n = 84), rifabutin 300 mg orally once daily (n = 47) or no prophylaxis (n = 61). Main outcome measures: Positive blood culture for M. avium complex (MAC), time to development of dMAC, and time to death. Results: When compared with no prophylaxis or rifabutin, the incidence of dMAC and time to development of dMAC were improved among those patients receiving clarithromycin (P < 0.001). Prolonged survival was associated with both clarithromycin and rifabutin use when compared with no prophylaxis (P < 0.002). In patients who failed prophylaxis, resistance to clarithromycin and rifabutin was observed. Conclusions: In the era prior to protease inhibitor use, once daily clarithromycin at a dose of 500 mg was associated with a reduction in the incidence of dMAC, appeared to be superior to rifabutin, and was associated with prolonged survival in patients with advanced HIV disease.