Risk factors for failure to complete a course of latent tuberculosis infection treatment in Salvador, Brazil

Abstract

Background: Although treatment of latent tuberculosis infection (LTBI) is an essential component of tuberculosis (TB) control in countries such as the United States, it is not widely practiced in most TB-endemic countries.

Objective: To examine the practice of and adherence to LTBI treatment in a high-risk population in Brazil.

Design: We followed household contacts (HHCs) of patients hospitalized with pulmonary TB in Salvador, Brazil, for 6 months after they initiated LTBI treatment with isoniazid (INH). HHCs were asked to return to the hospital once a month for 6 months for follow-up visits and INH refills.

Results: Of 101 HHCs who initiated LTBI treatment, 54 (53.5%) completed the 6-month regimen. The risk of treatment non-completion was significantly higher in HHCs who reported side effects to INH (RR 2.69, 95%CI 1.3-5.8, P = 0.01), and in those who had to take two buses for a one-way trip to the hospital (RR 1.8, 95%CI 1.01-3.3, P = 0.04). Of the 101 HHCs, 29 (28.7%) did not return for any follow-up visits; these HHCs were significantly more likely to have a 2-bus commute to the hospital compared to HHCs who completed treatment (OR 20.69, 95%CI 2.1-208.4, P = 0.01).

Conclusion: Nearly 50% of HHCs at high risk for developing TB completed a 6-month course of LTBI treatment. Completion of LTBI treatment was most affected by medication intolerance and commuting difficulties for follow-up visits.