The Impact of Directly Observed Therapy on Preventive Treatment for Latent Tuberculosis Infection among Students in Dalian, China

Preventive treatment has an essential effect on latent tuberculosis infection (LTBI) [purified protein derivative (PPD) induration ≥15 mm]. Between 2010 and 2013, there were 6 tuberculosis (TB) outbreaks in the universities in Dalian, China. So far, in Dalian, the directly observed therapy (DOT) and full course management (FCM) were widely used in the preventive treatment of LTBI. However, it is yet to be determined which one of them has better efficacy. Therefore, the purpose of our study was to explore the performance of these two strategies for LTBI preventive treatment. The chi-square test and exact test were used to perform statistical analysis. In total, 794 LTBI patients were enrolled in this study, of which 443 were included in the DOT group and 351 in the FCM group. In 287 students who said ditto to take prophylactic treatment (DOT 149 and FCM 79), the compliance rate for the DOT group was 90.3% (149/165), while that for the FCM group was 64.8% (79/122). This difference between the two groups was statistically significant (χ2=28.03, P=1.19E-07). The DOT group showed an effective intervention rate of 81.5%, while that for the FCM group was 28.5%. Again, this difference was significant (χ2=56.17, P=6.63E-14). Further, in 228 students who truly started taking treatment, 26 cases exhibited various adverse reactions (11.4%, 26/228), the most frequent one being elevated liver enzyme levels (6.6%, 15/228). In addition, the major reason for the treatment interruption was adverse reactions in the DOT group, and 6 (28.6%) LTBI patients discontinued treatment due to the adverse reactions of the anti-TB drugs. We also performed a one-year follow-up after the completion of the 3-month treatment. Out of the 794 close contacts, a total of 9 cases (1.1%) developed active TB. These results show that DOT is an effective preventive treatment for LTBI and would play an irreplaceable role in improving preventive treatment adherence and treatment outcomes.