LAUSR

BACKGROUND Four months of rifampin treatment for latent tuberculosis infection is safer, has superior treatment completion rates, and is as effective as 9 months of isoniazid. However, daily medication costs are higher for a 4-month rifampin regimen than a 9-month isoniazid regimen. OBJECTIVE To compare health care use and associated costs of 4 months of rifampin and 9 months of isoniazid. DESIGN Health system cost comparison using all health care activities recorded during 2 randomized clinical trials. (ClinicalTrials.gov: NCT00931736 and NCT00170209). SETTING High-income countries (Australia, Canada, Saudi Arabia, and South Korea), middle-income countries (Brazil and Indonesia), and African countries (Benin, Ghana, and Guinea). PARTICIPANTS Adults and children with clinical or epidemiologic factors associated with increased risk for developing tuberculosis that warranted treatment for latent tuberculosis infection. MEASUREMENTS Health system costs per participant. RESULTS A total of 6012 adults and 829 children were included. In both adults and children, greater health system use and higher costs were observed with 9 months of isoniazid than with 4 months of rifampin. In adults, the ratios of costs of 4 months of rifampin versus 9 months of isoniazid were 0.76 (95% CI, 0.70 to 0.82) in high-income countries, 0.90 (CI, 0.85 to 0.96) in middle-income countries, and 0.80 (CI, 0.78 to 0.81) in African countries. Similar findings were observed in the pediatric population. LIMITATION Costs may have been overestimated because the trial protocol required a minimum number of follow-up visits, although fewer than recommended by many authoritative guidelines. CONCLUSION A 4-month rifampin regimen was safer and less expensive than 9 months of isoniazid in all settings. This regimen could be adopted by tuberculosis programs in many countries as first-line therapy for latent tuberculosis infection. PRIMARY FUNDING SOURCE Canadian Institutes of Health Research.