The prevalence of latent tuberculosis infection in patients with inflammatory arthritis and the diagnostic efficacy of different screening methods

Abstract

Objective: To investigate the prevalence of latent tuberculosis infection (LTBI) in patients with inflammatory arthritis, and to compare the efficacy of tuberculin skin test (TST) and QuantiFERON-TB Gold (QFT) in screening for LTBI in these patients. Method: Medical records of 149 patients with inflammatory arthritis admitted to inpatient of Peking University International Hospital from December 2015 to December 2017 (diagnosis with rheumatoid arthritis, ankylosing spondylitis, sero-negative spondyloarthropathy, psoriatic arthritis, or reactive arthritis) who accepted TST or QFT were collected. The information included gender, age, history of tuberculosis infection, calcifications presence in chest X-ray or chest CT, TST result, QFT result, medication history before test, and biological treatment and all the patients were made a follow-up. Results: The positive rate of TST was 18.2%(14/77) and that of QFT was 27.1%(26/96), and the overall consistency between the two tests was fair. The rate of LTBI diagnosed by QFT was 22.9%(22/96). The positive rate of TST in patients older than 50 years was significantly higher than those younger than 50 years, but there was no significant difference between the two groups screened by QFT. The M-N values in QFT were decreased in both the patients above the age of 50 and in the patients using immunosuppressive agents. A total of 64 patients accepted biological agent therapy, and in those with a positive result of TST or QFT, only 2 cases received anti-LTBI treatment, but the other 14 cases without anti-LTBI treatment. None of them developed active tuberculosis in the following 3-24 months. Conclusion: The prevalence of LTBI in patients with inflammatory arthritis is consistent with that reported in rheumatoid patients, which is higher than in general people. In patients with inflammatory arthritis older than 50 years, especially those accepted immunosuppressive agents therapy, the immunity may be impaired and QFT is more sensitive than TST for screening LTBI.