Interventions for Tuberculosis Control and Elimination 2002

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Figure 80. Protection from isoniazid preventive therapy against tuberculosis among
HIV-infected persons. 884-888
with a rifampicin plus pyrazinamide containing regimen. 885 They were followed
up for a median of 1.8 years. The main outcome measures were
incidence of tuberculosis and death. Among those with a tuberculin skin
test reaction of five or more millimeters of induration, the point estimate
of protection from isoniazid was 74%, yet because of the small number,
the confidence intervals were wide and included zero. There was no difference
in mortality between preventive chemotherapy and placebo groups.
An important observation was that the effect of preventive chemotherapy
declined following cessation of treatment so that by 18 months after the
completion of therapy incidence rates in treated and non-treated groups were
the same.
In Kampala, Uganda, HIV-infected patients were enrolled in a randomized
trial to receive one of four arms: placebo, isoniazid for six months,
or two rifampicin-containing regimens (one with, the other without pyrazinamide).
Among patients with a tuberculin skin test reaction of five or
more millimeters of induration, isoniazid reduced the risk of tuberculosis
over a mean follow-up time of 15 months by 67%. 886 Survival did not
differ between the groups.
Collaborating centers in New York City and elsewhere conducted a
randomized trial to assess the efficacy of isoniazid in patients with HIV
infection who were anergic. 887 Anergy was defined as reacting with more
than five millimeters of induration to tuberculin and less than two millimeters
to both mumps antigen and tetanus toxoid. Patients were addi-
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