Abstract 27 — Prevalence and Management Approach of Latent Tuberculosis Infection in Rheumatology Patients

Prior to immunosuppression, rheumatology patients are routinely screened for latent tuberculosis infection (LTBI) using Interferon-Gamma Release Assays (IGRA). The management of latent and indeterminate IGRA results varied among institutions and long-term outcome data is lacking. We conducted a retrospective study at Tawam Hospital, United Arab Emirates, to examine the frequency and management of positive and indeterminate IGRA results and tuberculosis infection in rheumatic patients. Methods Laboratory records and hospital electronic medical system were used to obtain information about IGRA results over a 12 years period (April 2010-April 2022). Results In our hospital record over a 12-year period, we found a total of 1012 positive and 223 indeterminate IGRA test results. Within the rheumatology department, 123 positive and 39 indeterminate IGRA results were identified. In the indeterminate IGRA group, the majority were female (n=24, 61.5%), UAE nationals (n=22, 56.4%), and had a mean age of 38.6 years. Systemic lupus erythematosus (SLE) was the most prevalent rheumatologic condition (n=21, 53.8%). 33.3% (n=13) were on disease modifying anti-rheumatic drugs (DMARDs) and 66.7% (n=26) were on corticosteroid during IGRA testing. A total of 8 patients (20.5%) received anti-TB medications. In a positive IGRA group, the mean age of 55.7 years and a female-to-male ratio of 3:1. The most common rheumatologic conditions were RA (n=67, 54.4%). Approximately 52.8% (n=65) of patients were on conventional DMARDs, 66.7% (n=26) were on corticosteroids during IGRA testing, and 60% (n=74) received anti-TB medications. Two cases (1.6%) of active TB infections were detected among patients with positive IGRA tests, both of whom were receiving anti-TNFa inhibitor treatment in combination with methotrexate. No cases of active TB infection were observed in the indeterminate IGRA group. Conclusion Tuberculosis risk in positive and indeterminate IGRA results for rheumatological conditions is low. Further multicenter studies are required to analyze patient outcomes and differences in TB-endemic and non-endemic regions.