Outcomes of latent tuberculosis infection treatment in Istanbul

Increasing the extensity of latent tuberculosis infection (LTBI) treatment which is one of the important parameters of tuberculosis (TB) control and completing the treatment in success are important. The purpose of this study is to evaluate LTBI treatment indications and treatment outcomes of patients who received LTBI treatment in İstanbul between 2016 and 2018.

The treatment outcomes of people who started LTBI treatment registered in TB dispensaries in Istanbul between 2016 and 2018 were analyzed retrospectively according to the variables of the age groups, gender, dispensary subgroups, and prevention treatment indications. Data collected from the health institutions were evaluated.

26.920 patients received LTBI treatment in all Istanbul TB dispensaries between 2016 and 2018. The evaluation of LTBI treatment indications; contact 15.696, Tuberculin skin test (TST) positivity 2224, immunosuppression 8746, TST conversion 58, sequelae lesion 15, and other indications are identified as 181. The groups which diagnosed with TB disease, mortality, transfer, other, and still in treatment are excluded from the analysis of LTBI treatment outcomes. A total of 25.253 patients were analyzed. 65 percent of the patients had completed LTBI treatment. Variables effective for treatment outcomes are analyzed with logistic regression. Treatment discontinuation was statistically significantly lower in 2017 (odds ratio [OR]: 0.906 confidence interval [CI] [95%] [0.849-0.968]) and 2018 (OR: 0.635 CI [95%] [0.594-0.679]) compared to 2016. Treatment lost to follow-up was statistically significantly lower in those receiving LTBI treatment with the indication of tuberculin skin test positivity (OR: 0.541 CI [95%] [0.487-0.600]) and the indication of immunosuppression (OR: 0.284 CI [95%] [0.142-0.569]) compared to those who received LTBI treatment due to contact. When the treatment results are evaluated according to the TB incidence of the region where the dispensaries are located, treatment lost to follow-up was higher in 101-200 per 100,000 incidence group (OR: 1.201 CI [95%] [1.123-1.285]) and incidence of 201-370 per 100,000 (OR: 1.461 CI [95%] [1.358-1.572]). Treatment lost to follow-up was higher in dispensaries on the European side (OR: 1.293 CI [95%] [1.203-1389]) and the 0-35 age group (OR: 1.248 CI [95%] [1.168-1.333]).

In conclusion, the treatment completion rate should be improved for an effective LTBI treatment which is one of the important parameters of targeted TB elimination. Particularly people under the age of 35 years and regions with high-TB incidence should receive special care and close follow-up.