Tuberculosis screening in patients receiving biological therapy

Introduction: Portuguese recommendations propose universal screening for TB before starting biologics and then annually if screened negative. Aim: To characterize i)biologics candidates9 baseline screening (BS) results ii)conversions of immunodiagnostic tests iii)development of active TB during follow-up iv)compliance with screening recommendations. Methods: Patients screened for TB at a reference centre before starting biologics between 2008-2012 were identified. Medical files were retrospectively reviewed. Demographic data, screening and follow-up results and information on biological therapy were collected. Exclusion criteria: unavailable data on biologics9 initiation. Results: 183 patients were included in the study, with 115 starting biologics - 45(39,1%) had Psoriasis, 21(18,3%) Crohn9s Disease, 21(18,3%) Multiple Sclerosis, 12(10,4%) Ankylosing spondylitis, 8(7%) Rheumatoid Arthritis and 8(7%) had other pathologies. The BS was positive in 52(45,2%) patients. Patients with positive BS did not develop active TB during follow-up. Of the 63(54,8%) patients who screened negative, 2(3,17%) developed active TB (under anti-TNFα) more than 1 year after starting biologics. 26 patients were re-screened at the TB centre. 5(19,23%) had TST conversion and one concomitantly undetermined IGRA. No IGRA conversions were observed. Conclusion: The rate of latent TB at BS was higher than expected. No patients with positive BS developed active TB. The rate of re-screening suggests a low awareness to recommendations. Efforts should be made to raise awareness to the risk of TB exposure, since the active TB cases suggested new infection. Nationwide studies are necessary to evaluate the efficacy of the re-screening strategy.