Frequency of Latent TB Infection in Patients with Spondyloarthritis in a Tertiary Care Hospital in Bangladesh

Abstract

Background & Objective: Screening for latent TB infection is recommended prior to the initiation of the newer and more effective treatment modalities of spondyloathritis such as biologic agents and tofacitinib. The prevalence of latent TB infection in the adult population of Bangladesh is not yet known. The figure is 40% in the general population in India that is demographically similar to the Bangladeshi population. The objective of this study was to assess the frequency of latent TB infection in patients with spondyloarhtritis visiting a tertiary hospital. Materials & Methods: This study was conducted in the Department of Rheumatology of Enam Medical College & Hospital, Savar, Dhaka, Bangladesh from October 2018 to December 2019. Each of the 75 participants underwent Mantoux test as a screening procedure for the detection of latent TB infection. Results: Mantoux test was positive (≥10 mm) in 10.3% of the participants. A reading between 5 and 9 mm was found in 33.7% of the participants and the rest of the participants (56%) had induration diameters <5 mm). 44% of the participants had readings ≥5 mm. Conclusions: A lower than expected (around 40%) frequency of latent TB infection was found among the participants. But using a cut-off value of 5 mm yields a frequency of 44%% that is close to our expectation. So a lower cut-off value for the interpretation of Mantoux test in patients with spondyloarthritis may be appropriate. A larger-scale study is required to confirm this observation.