[Randomized trial of three regimens to prevent tuberculosis in HIV-infected patients with anergy]

To evaluate the efficacy of three regimens of prophylactic therapy for tuberculosis in HIV-infected patients with anergy.

Prospective, multi-center, randomized, comparative, and open clinical trial. Anergy was defined as absence of induration in response to three antigens (PPD, Candida albicans and parotiditis antigen) applied by the Mantoux method. Patients were randomized into one of the following prophylactic treatment groups: isoniazid for six months (6H), rifampin plus isoniazid for three months (3RH), rifampin plus pyrazinamide for two months (2RZ) or no treatment (NT). After completion of treatment, patients were followed up for two years.

A total of 319 patients were included in the study, 83 in the 6H regimen, 82 in 3RH, 77 in 2RZ and 77 in NT. The observation period following treatment was 88, 96, 81 and 126 person-years, respectively, for 6H, 3RH, 2RZ and NT. There were 11 cases of tuberculosis during the follow-up period. The tuberculosis rates (cases per 100 person-years) were 3.4, 3.1, 1.2 and 3.1 for 6H, 3RH, 2RZ and NT respectively, with relative risks in regimens 6H, 3RH and 2RZ with respect to NT of 1.07 (0.24-4.80), 0.98 (0.22-4.4) and 0.39 (0.04-3.48), all statistically non-significant. Twenty-nine patients died during the follow-up period, none due to tuberculosis, and no appreciable differences were found among the groups.

The results showed no significant decrease in the risk of developing tuberculosis with any of the evaluated regimens and, therefore, do not support the use of antituberculosis chemoprophylaxis in anergic HIV-infected patients.