Effects of preventive therapy for latent tuberculosis infection and factors associated with treatment abandonment: a cross-sectional study.

BACKGROUND: Routine data on the use of preventive therapy (PT) for latent tuberculosis infection (LTBI) in students are scarce in high tuberculosis (TB) burden countries. This study aimed to investigate the effects of PT and identify factors related to PT abandonment during the school TB epidemic in Guangzhou, southern China. METHODS: Purified protein derivative (PPD) skin testing was performed on all staff and students in a vocational school in Guangzhou, southern China during December 2014. Subjects (n=362) with a reactive PPD induration ≥15 mm, or with papules, blisters, and a normal chest X-ray image were recommended for PT. The subjects were assigned to a PT group (n=156) and control group (n=206), respectively, on a voluntary basis. Subjects in the PT group received isoniazid (INH) combined with rifampicin (RFP) for 3 consecutive months; after which, the incidence of TB and protective rate of PT for reducing TB were observed during a 2-year follow up period. An improved questionnaire was used to identify factors that influenced treatment abandonment. All data were subjected to univariate and multivariate logistic regression analyses. RESULTS: Two cases in the PT group and 20 cases in the control group developed TB. The protective rate of PT for reducing TB was 86.8%. In the PT group, 69 cases finished PT, with a completion rate of 44.2%, and the incidence rates of adverse events and hepatotoxicity were 12.2% and 1.9%, respectively. Among 362 LTBI cases, a total of 293 cases abandoned PT. Discrimination (OR =7.173, 95% CI, 3.361-15.307), worry about adverse drug reactions (OR =2.752, 95% CI, 1.459-5.192), a low parental education level (OR =2.605, 95% CI, 1.420-4.777), and accepting the opinion of a non-TB specialist (OR =6.017, 95% CI, 3.077-11.765) were identified as high-risk factors for abandoning PT. CONCLUSIONS: A PT regimen consisting of INH combined with RFP for 3 consecutive months is reasonable for use in schools. Discrimination, worry about adverse drug reactions, a low parental education level, and accepting the opinion of a non-TB specialist are all factors that may increase the risk for treatment abandonment among LTBI cases. To overcome psychological obstacles is critical for improving treatment adherence.