Arias-Guillén M, Sánchez Menéndez MM, Alperi M, Riestra S, González Budiño MT, García-Clemente MM, Martínez-González S, Enríquez AI, Alonso-Arias R, Palacios Gutiérrez JJ, Santibáñez M, Coto-Segura P, Camblor PM, García-Alfonso L, Morante I, Escalante P. High rates of tuberculin skin test positivity due to methotrexate therapy: False positive results?
Semin Arthritis Rheum 2018;
48:538-46. [PMID:
29735171 DOI:
10.1016/j.semarthrit.2018.03.018]
[Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 03/01/2018] [Accepted: 03/26/2018] [Indexed: 11/20/2022]
Abstract
RATIONALE
The tuberculin skin test (TST) and interferon ? release assays (IGRAs) are commonly used for latent tuberculosis infection (LTBI) screening. Unexpectedly high TST positivity rates have been reported in patients with rheumatic diseases, and methotrexate is frequently used in this population. We hypothesized that methotrexate use could be associated with false-positive TST results.
OBJECTIVES
To investigate whether treatment with methotrexate and other factors are associated with false-positive TST results in patients with rheumatic diseases.
METHODS
Prospective single-center study conducted between April 2013 and March 2016. Adult patients with rheumatic diseases were evaluated with a TST and two IGRAs for LTBI screening. We compared TST and IGRA results in patients treated and not treated with methotrexate and analyzed for factors associated with positive TST results.
CONCLUSIONS
Our data suggest false-positive TST results associated with methotrexate therapy. Thus, we recommend against using the TST for LTBI screening in patients receiving methotrexate and the preferential use of IGRAs in such patients.
MEASUREMENTS AND MAIN RESULTS
We studied 393 patients with rheumatic diseases, including ankylosing spondylitis (ASP, n = 90), rheumatoid arthritis (RA; n = 120), psoriatic arthritis (PA, n = 126), and other disorders (n = 57). The rate of TST positivity varied across the groups: ASP 22.2%, RA 25%, PA 35.7%, and other disorders (22.8%). Positivity rates were lower with IGRAs. Methotrexate use was associated with a statistically significant two-fold increase in the risk of a positive TST and a dose\x96 response relationship was observed. We found no statistically significant associations between methotrexate use and IGRA test positivity.
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