A141 CONCORDANCE BETWEEN TUBERCULIN SKIN TEST AND INTERFERON GAMMA RELEASE ASSAY FOR LATENT TUBERCULOSIS SCREENING IN INFLAMMATORY BOWEL DISEASE (META-ANALYSIS)

Abstract Background Screening for latent tuberculosis infection (LTBI) is mandatory prior to initiating anti-tumor necrosis factor (anti-TNF) medications. New guidelines recommend interferon-gamma release assays as first line screening method for the general population. Studies have provided conflicting evidence on the performance of interferon-gamma release assays (IGRAs), compared to tuberculin skin test (TST) in inflammatory bowel disease (IBD) patients. We assessed the concordance of these two tests in IBD patients and the effect of immunosuppression on their performance. Aims We performed a systematic search of MEDLINE, EMBASE and Cochrane Library databases, from 2011 to 2016, for relevant studies testing both TST and IGRA in IBD patients. The primary outcome was concordance between TST and IGRA. Secondary outcomes were effects of immunosuppressive therapy on both TST and IGRA. Immunosuppression was defined as either steroids more than 5 mg for at least two weeks, thiopurine, methotrexate or cyclosporine. Methods We used the Mantel-Haenszel method for a pooled random effects model, given heterogeneity of studies included. We also compared the fixed effects model to exclude any effect of smaller studies. Heterogeneity between studies was analysed using the statistical I2, Q and Tau 2 tests. The quality of included studies was evaluated using a modified QUADAS-2 method. Results Sixteen studies, including 2488 patients with IBD, were included for the analysis. The pooled concordance between the TST and IGRA was 85% (95% confidence interval [CI] 81%-88%, p=0.01). Effects of immunosuppression on both tests were reported in eight studies including 814 patients with IBD. The odds ratio of testing positive by IGRA decreased to 0.57 if immunosuppressed (95% confidence interval [CI] 0.31–1.03, p=0.06). The odds ratio of testing positive by TST if immunosuppressed was 1.14 (95% confidence interval [CI] 0.61–2.12, p=0.69). Using the fixed effect model yielded similar results, however the negative effect of immunosuppression on IGRA reached statistical significance (p=0.06 to 0.01). Conclusions While concordance was 85% between TST and IGRA, the performance of IGRA seems to be negatively affected by immunosuppression. Given the importance of detecting latent TB prior to anti-TNF initiation, using only IGRA should be avoided in immunosuppressed IBD patients. Pooled concordance of TST and IGRA in all IBD patients. Funding Agencies None