QuantiFERON®-TB Gold In-Tube test can be used for screening latent tuberculosis before biological treatment in a Bacille Calmette-Guérin (BCG)-vaccinated country: the HUR-BIO single-center real-life results.

objectivesThe Turkish population is vaccinated with Bacille Calmette-Guérin (BCG), and the BCG vaccination decreases the specificity of the tuberculin skin test (TST). The purpose of this study was to investigate the incidence of active tuberculosis (TBC) among rheumatic patients who were screened only with the QuantiFERON®-TB Gold In-Tube (QFT-GIT) test for latent TBC prior to biological treatment.

methodsThe Hacettepe University Biological Database (HUR-BIO) was used for latent TBC assessment. Consecutive patients were evaluated from July 2015 to October 2016 by a questionnaire that included the patients' demographic characteristics, treatment history, and symptoms of active TBC. A total of 664 patients were interviewed by physicians. TBC statuses of the 671 non-interviewed patients were checked from the Turkish National Tuberculosis Registry records. Mean TBC incidence per year was calculated for anti-tumor necrosis factor-alpha (TNF-α) agents.

resultsA total of 1335 (58.2% female) patients with the mean age of 44.2 ± 12.9 years were included. Of the patients, 836 (62.6%) had spondyloarthropathy, 432 (32.4%) had rheumatoid arthritis, and 67 (5%) had other rheumatologic diseases. The total biological drug exposure was 2292 patient-years (2043 patient-years for anti-TNF-α, 249 patient-years for non-TNF-α inhibitors). Positive and indeterminate QFT-GIT results were found in 258 (19.3%) and 23 (1.7%) patients, respectively. The median follow-up time after the onset of biological agent was 19.4 months (IQR = 29.5). Pulmonary TBC was found in 3 (0.2%) of the 1335 patients. The annual incidence of TBC was 147/100,000 patient-years for all TNF-α inhibitors (249/100,000 and 123/100,000 patient-years for QFT-GIT-positive and negative patients, respectively).

conclusionsTBC incidence increased by nearly seven times the Turkish national TBC incidence. The QFT-GIT Test appears acceptable to determine latent TBC before biological agent use. Consequently, the QFT-GIT Test can be appropriately used in BCG-vaccinated countries. Key Points • Our study contributes to filling the gap in the literature by reflecting real-life data about TBC frequency after QFT-GIT use in patients receiving biological agents. • The frequency of active TBC will remain within acceptable limits when only QFT-GIT is used in the screening of latent TBC prior to the use of biological agents in a population where the majority are vaccinated with BCG. • Using the QFT-GIT alone for latent TBC screening prior to biologic treatment in countries with high BCG vaccination rates reduces the number of patients needing isoniazid (INH) treatment.