Abstract
Introduction Systemic biologic agents can increase the risk of reactivation of latent tuberculosis (TB). Prior to initiation, screening for latent TB using an interferon-γ (IFN-γ) release assay (IGRA) is recommended. There is concern that false negative IGRAs may be more likely in this context.
Methods This retrospective analysis of IGRA, specifically TSPOT.TB, results and outcomes of patients already on or due to start biologics identifies the rate of TB reactivation in a low TB incidence setting. Additionally, we estimate the negative predictive value (NPV) of IGRAs in this population.
Results Patients on biologics were more likely to have a negative IGRA result than patients not on biologics. There was no statistically significant change in conversion or reversion rates between groups. Of 9263 patients on biologics, 19 developed active TB after starting biologics at an incidence of 55.1 per 100 000 patient years. This occurred despite screening in half of the 16 patients for whom we were able to review medical records. Most drugs implicated were known to be high risk, although rituximab and natalizumab were being taken by 5 patients and 1 patient respectively. The TSPOT.TB NPV was 99.20% and dropped only slightly to 99.17% when we simulated an approach where all borderline IGRA results were regarded as being negative.
Conclusion Negative IGRA results confer a low risk of subsequent active TB in patients on biologics in a low incidence setting. However, continued awareness is needed given that a number of active TB cases will have had a prior negative result.
Footnotes
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Conflict of interest: John Cafferkey reports the following relationships outside the submitted work; grants or contracts from Royal College of Emergency Medicine, NHS Lothian and University of Edinburgh; support for attending meetings and/or travel from Edinburgh Anaesthesia Research and Education Fund; current member of Regional Ethics Committee, South East Scotland.
Conflict of interest: Mikin Patel reports the following relationships outside the submitted work; consulting fees received from Takeda and Jansen; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Jansen – Guidelines in Practice; support for attending meetings and/or travel from Jansen; participation on a Data Safety Monitoring Board or Advisory Board for Takeda, Pfizer, Jansen, Celltrion and Mylan.
Conflict of interest: Kartik Kumar received support for the present manuscript from National Institute for Health Research (NIHR) Imperial Biomedical Research Centre (BRC)- Funding for clinical PhD and salary at Imperial College London, Lee Family endowment to the Faculty of Medicine at Imperial College London - Funding for clinical PhD and salary at Imperial College London.
Conflict of interest: Mirae Park received support for the present manuscript from Funded by the National Institute for Health Research (NIHR) Imperial Biomedical Research Centre (BRC).
Conflict of interest: Aneeka Chavda reports the following relationships outside the submitted work; received an honoraria for manuscript form Shiongi for case report on Cefidericol.
Conflict of interest: Meg Coleman reports the following relationships outside the submitted work; received payment from Gilead support for educational lectures talks.
Conflict of interest: The remaining authors have nothing to disclose.
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- Received April 26, 2022.
- Accepted August 17, 2022.
- Copyright ©The authors 2022
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