Rifampin appears less costly than isoniazid for latent TB treatment
Data from two randomized clinical trials in adults and children found that both health system use and costs were higher with nine months of isoniazid versus four months of rifampin.
A four-month regimen of rifampin may be a less expensive option than a nine-month course of isoniazid for treatment of latent tuberculosis (TB) infection, a new study found.
Researchers used data from two randomized clinical trials to compare health care use and associated costs for each regimen in patients with latent TB across high-income, middle-income, and African countries. In the trials, adults and children who had a documented positive result on a tuberculin skin test or interferon-gamma release assay, a clinical or epidemiologic risk factor associated with increased risk for active TB, and a recommendation for latent TB treatment from their treating physician were randomly assigned to receive four months of rifampin or nine months of isoniazid. The current study's main outcome measure was health system costs per participant. Results were published June 16 by Annals of Internal Medicine.
Overall, data from 6,012 adults and 829 children were included in a modified intention-to-treat analysis. Seventy-one percent of adults and 82% of children completed treatment. Both adults and children had more health system use and higher costs with nine months of isoniazid than with four months of rifampin. Total costs in adults were significantly lower with rifampin than with isoniazid, with the highest costs per participant seen in high-income countries ($549.10 with rifampin vs. $725.40 with isoniazid). Mean ratios of costs of rifampin versus isoniazid among adults were 0.76 (95% CI, 0.70 to 0.82) in high-income countries, 0.90 (95% CI, 0.85 to 0.96) in middle-income countries, and 0.80 (95% CI, 0.78 to 0.81) in African countries. Findings in children were similar.
The authors noted that costs may have been overestimated because a minimum number of follow-up visits were required, among other limitations. However, they concluded that although daily costs for rifampin are usually higher than those for isoniazid, a four-month regimen of the former appears less costly than a nine-month regimen of the latter in terms of overall health care system use, including visits, blood tests, and care for adverse events. “Implementation of a regimen should consider not only drug procurement costs but also overall health system costs, including treatment and follow-up,” they wrote. “Therefore, the higher costs of the pills should not prevent the adoption of 4 months of rifampin by tuberculosis programs in resource-limited settings.”