532. Usefulness of simultaneous performance of an IGRA and TST for latent tuberculosis screening in rheumatology patients. Influence of disease and treatment
Session: Poster Abstract Session: Latent Tuberculosis Diagnosis and Management
Thursday, October 27, 2016
Room: Poster Hall
  • Slide1.PNG (3.1 MB)
  • Background:TNF-α inhibitors are known to increase susceptibility to TB because they impair granuloma formation and maintenance. Tuberculin skin test (TST) and Interferon gamma relay assays (IGRAS) are recommended for screening latent TB infection (LTI) in candidates to receive TNF-α inhibitors treatment. Spanish guidelines recommend treatment with Isoniazid if any of the test is positive. The influence of the type of rheumatic disorder or its treatment on the discrepancies between the two tests is unknown.

    Our objective was to prospectively evaluate the results of TST and QFT in rheumatology patients in different therapeutic phases.

    Methods: All adults with inflammatory arthritis assisted in a hospital out-clinic were derived for enrollment, excluding patients on treatment with >10 mg/d of Prednisone or with active TB. All of them were studied with X-ray, QFT [Cellestis®] and PPD (0.1 mL of the PPD RT23). Structured interview was performed to collect epidemiological and clinical factors. Therapy of the rheumatic disease was classified as follow: Phase 1: anti-inflammatories; Phase 2: disease-modifying antirheumatic drugs; Phase 3: biologic therapy.

    Results: From March 2011 to June 2014, 202 were enrolled. Underlying conditions were: 134 peripheral arthritis (PA), 49 central arthritis (CA) and 19 “other connective tissue disorders” (OC). The three groups were comparable according to TB epidemiological indicators. The global index of agreement between QFT and TST was moderate (kappa: 0.460) no differences according to treatment phase (1: 0.331, 2: 0.380, 3:0.419) or type of rheumatic disorder (PA: 0.460, AS: 0.459, OC: 0.477). The main discrepancy, PPD+/QFT- (39 patients, 19%) was only statistically associated to prior BCG vaccination (p<0.001) even in patients with TB epidemiological indicators. QFT+/PPD- was an unusual result (8 patients, 4%) but mainly appeared in patients in phase 1 with a shorter length of rheumatic disease (p=0.04). INH hepatotoxicity (6/60) was always mild. Clinical follow-up of enrolled patients is still on going. There was no case of TB.

    Conclusion: In our environment, QFT and TST should be used simultaneously in patients with rheumatology diseases in order to detect the highest number of rheumatology candidates to receive INH. We could not find any impact of type of disease or previous treatment.

    Paloma Gijón, MD/PhD1, Patricia Muñoz, MD/PhD2, María Jesús Ruiz-Serrano, Pharm2, María Montoro, MD/PhD3, Martha Kestler, MD/PhD4, Oihane Aldecoa-Otarola, MD2 and Emilio Bouza, MD, PhD2, (1)Microbiología, Hospital Gregorio Marañón, Madrid, Spain, (2)Microbiology, Hospital Gregorio Marañón, Madrid, Spain, (3)Rheumatology, Hospital Gregorio Marañón, Madrid, Spain, (4)Hospital Gregorio Marañon, Madrid, Spain


    P. Gijón, None

    P. Muñoz, None

    M. J. Ruiz-Serrano, None

    M. Montoro, None

    M. Kestler, None

    O. Aldecoa-Otarola, None

    E. Bouza, None

    Findings in the abstracts are embargoed until 12:01 a.m. CDT, Wednesday Oct. 26th with the exception of research findings presented at the IDWeek press conferences.