n Southern African Journal of HIV Medicine - Efficacy of secondary isoniazid preventive therapy among HIV-infected Southern Africans : time to change policy?

Volume 2004, Issue 16
  • ISSN : 1608-9693
  • E-ISSN: 2078-6751



<I>Objective</I>. To determine the efficacy of secondary preventive therapy against tuberculosis (TB) among goldminers working in South Africa. <br><I>Design</I>. An observational study. <br><I>Methods</I>. The incidence of recurrent TB was compared between two cohorts of HIV-infected miners: one cohort had received secondary preventive therapy with isoniazid and the other had not. <br>Setting. Health service providing comprehensive care for goldminers. <br>Participants. 338 men received secondary preventive therapy and 221 did not. <br><I>Main outcome measure</I>. Incidence of recurrent TB. <br><I>Results</I>. The overall incidence of recurrent TB was reduced by 55% among men who received isoniazid preventive therapy (IPT) compared to those who did not (incidence rates 8.6 and 19.1 per 100 person-years respectively, incidence rate ratio 0.45; 95% CI 0.26 - 0.78). The efficacy of isoniazid preventive therapy was unchanged after controlling for CD4 count and age. The number of person-years of isoniazid preventive therapy required to prevent one case of recurrent TB among individuals with a CD4 count < 200/µl and >200/µl was 5 and 19, respectively. <br><I>Conclusion</I>. Secondary preventive therapy reduces TB recurrence: the absolute impact appears to be greatest among individuals with low CD4 counts. International TB preventive therapy guidelines for HIV-infected individuals need to be expanded to include recommendations for secondary preventive therapy in settings where TB prevalence is high.

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