Treatment of latent tuberculosis in persons at risk for multidrug-resistant tuberculosis: Systematic review

SETTING: The emergence and spread of multidrug-resistant tuberculosis (MDR-TB), caused by Mycobacterium tuberculosis resistant to at least isoniazid (INH) and rifampicin, is a threat to global TB control. OBJECTIVE: To appraise evidence of the effectiveness of treatment of latent TB infection (LTBI) in people at risk for developing active MDR-TB. DESIGN: Systematic review of comparative studies of people treated and not treated for LTBI following exposure to MDR-TB. DATA SOURCES: PubMed, EMBASE, LILACS and the Cochrane Library (December 2004). RESULTS: Two observational studies met inclusion criteria. A prospective cohort study found individualised tailored treatment to be effective for preventing active TB in children (OR = 0.20, 95% CI 0.04-0.94), while a retrospective cohort study found INH not to be effective (OR = 0.46, 95% CI 0.07-2.32). CONCLUSION: Evidence of the effects of treatment of LTBI in people exposed to MDR-TB is extremely limited in both quantity and quality. The increasing global spread of MDR-TB and the difficulties in treating it emphasise the need for effective preventive measures. Ideally, this issue should be addressed in a randomised controlled trial. Until such a trial is conducted, routine clinical data collected as part of existing TB control programmes could be useful and can be generated relatively easily.