Latent tuberculosis infection screening in patients with inflammatory bowel disease: a nationwide retrospective cohort study in South Korea comparing IGRA alone versus a combination of TST and IGRA

BACKGROUND/AIMS: We aimed to evaluate if using the interferon-gamma release assay (IGRA) alone is effective for latent tuberculosis infection (LTBI) screening in preventing active tuberculosis in patients with inflammatory bowel disease (IBD) before initiating anti-tumor necrosis factor alpha (anti-TNF-α) therapy, compared to using both the tuberculin skin test and IGRA. METHODS: Using South Korea's Health Insurance Review and Assessment Service, we selected IBD patients treated with anti-TNF-α agents for ≥ 1 year who underwent LTBI screening between 2018 and 2021. We compared the 1-year incidence rate and standardized incidence ratio of active tuberculosis incidence after starting anti-TNF-α treatment to the general population based on the LTBI screening strategy. RESULTS: Of the 4,215 enrolled patients, 3,505 underwent IGRA alone for LTBI screening, while 710 received both tuberculin skin test and IGRA. Within 1 year of starting anti-TNF-α treatment, 15 patients (0.36%) developed active tuberculosis, with a mean follow-up period of 4,200.6 person-years. The 1-year tuberculosis incidence rates were 372.3 (95% confidence interval [CI], 198.2-636.6) per 100,000 person-years for the IGRA alone group and 282.3 (95% CI, 34.2-1,019.9) per 100,000 person-years for the combination group. The standardized incidence ratios were similar: 14.34 (95% CI, 7.63-24.52) for the IGRA alone group and 11.25 (95% CI, 1.26-40.61) for the combination group. CONCLUSIONS: Using IGRA alone may be an effective strategy for LTBI screening in IBD patients before starting anti-TNF-α therapy. (Intest Res, Published online ).