Date Published: July 5, 2018
Publisher: Public Library of Science
Author(s): Dae Hyun Jeong, Jieun Kang, Young Ju Jung, Bin Yoo, Chang-Keun Lee, Yong-Gil Kim, Seokchan Hong, Tae Sun Shim, Kyung-Wook Jo, Joan A. Caylà.
This study aims to compare the latent tuberculosis infection (LTBI) screening strategy of interferon-gamma release assay (IGRA)-alone and in combination with tuberculin skin tests (TSTs) before the initiation of tumor necrosis factor (TNF) inhibitor treatment in patients with inflammatory arthritis. Between January 2011 and June 2017, we enrolled 476 patients who were followed up for ≥1 year after the TNF inhibitor initiation in a tertiary referral center in South Korea. Inflammatory arthritis comprised rheumatoid arthritis in 266 (55.9%) and ankylosing spondylitis in 210 (44.1%) patients. The following strategies were used for LTBI screening during the study period: (i) from January 2011 to October 2014, the combination of TST and QuantiFERON-TB Gold In-Tube (QFT-GIT); (ii) between November 2014 and February 2015, QFT-GIT-alone and (iii) since March 2015, either the combination of TST and QFT-GIT or QFT-GIT-alone depending on the attending physician’s choice. We compared the screening strategies of QFT-GIT alone and in combination with TST. Overall, 338 (71.0%) patients received LTBI screening tests using the combination of TST and QFT-GIT, and 138 (29.0%) received QFT-GIT-alone. In addition, the LTBI tests were positive in 159 (47.0%) of 338 patients using the combination tests, and 43.8% (148/338) required LTBI treatment. Meanwhile, the LTBI tests were positive in 32.6% (45/138) of QFT-GIT-alone patients, and 30.4% (42/138) required LTBI treatment. Among 338 patients who received combination tests, 2 patients developed active tuberculosis within 1 year after the TNF inhibitor initiation. Of patients who received QFT-GIT-alone, no patient developed tuberculosis. In conclusion, among patients who received QFT-GIT-alone, the number of patients who required LTBI treatment declined compared to the TST and QFT-GIT combination, and none developed active tuberculosis within 1 year, suggesting that QFT-GIT-alone could be a potential screening strategy for diagnosing LTBI in patients with inflammatory arthritis in South Korea.
Tumor necrosis factor (TNF) inhibitor has been increasingly used in the treatment of inflammatory arthritis, including rheumatoid arthritis (RA) and ankylosing spondylitis (AS), with profound effect [1, 2]. However, patients treated with TNF inhibitors are at increased risk of developing tuberculosis, predominantly through the reactivation of latent tuberculosis infection (LTBI) . Owing to the dramatic reduction of the incidence of tuberculosis because of widespread screening and treatment of LTBI before the initiation of TNF inhibitors , screening for LTBI before starting therapy with TNF inhibitor is recommended .
Despite the increased use of a TNF inhibitor for inflammatory arthritis, optimal methods for LTBI screening in patients with inflammatory arthritis before the TNF inhibitor initiation remain controversial. Although several guidelines recommend (i) TST or IGRA-alone [10–12], or (ii) the combination use of TST and IGRA [24, 25] no study has compared these strategies directly. To the best of our knowledge, this is the first study to compare various LTBI screening methods, i.e., IGRA-alone versus the combination of TST and IGRA before the use of TNF inhibitor in patients with inflammatory arthritis. This study revealed that the number of patients who needed LTBI treatment was reduced among patients who received LTBI test using QFT-GIT-alone, compared with those who received LTBI test using the combination of TST and QFT-GIT. Besides, none developed active tuberculosis within 1 year after TNF inhibitor initiation among patients who received QFT-GIT-alone. These results suggest that QFT-GIT-alone could be used as a screening strategy for diagnosing LTBI in inflammatory arthritis patients in South Korea, where the incidence of tuberculosis is intermediate and BCG vaccination is mandatory at birth.