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The tuberculin skin test still matters for the screening of latent Tuberculosis infections among Inflammatory Bowel Disease patients

Digestive and Liver Disease

Abstract

Background and Aims

There is a high risk of Tuberculosis among patients medicated with anti-tumour necrosis factor α (anti-TNFα) that can be mitigated by treating latent Tuberculosis infections (LTI). This study aimed to evaluate the performance of Tuberculin Skin test (TST) and Quantiferon-TB Gold in Tube (QFT-GIT) in a population of patients suffering from Inflammatory Bowel Diseases.

Methods

The cohort analysed in this study consisted of 250 patients, of whom 15% were therapy-naïve and 85% were medicated: 70% under immunosuppressive therapy and 30% on anti-TNFα. A LTBI was diagnosed following a positive result in either of the tests and their performance and concordance were evaluated.

Results

Fifty-eight and 24 patients had a positive TST and QFT-GIT, respectively. In 72 (29%) patients LTBI was diagnosed, of whom 8 (21%) were therapy-naïve. TST had an overall higher sensitivity (81% vs. 35%) and a higher Negative Predictive Value (93% vs. 80%) when compared to QFT-GIT test; this superiority was consistently maintained irrespective of the presence and kind of backbone immunosuppressive therapies. The concordance between both tests was weak.

Conclusions

Our results underscore the need to maintain the TST on LTBI diagnosis in patients about to start or switch anti-TNFα therapy in an intermediate Tuberculosis incidence context.

Keywords: anti-TNFα, QuantiFERON-TB Gold In-Tube.

Footnotes

a Infectious Diseases department, Centro Hospitalar de São João, Porto, Portugal

b Master of Science, Department of Sciences of Information and Decision in Healthcare, Faculdade de Medicina da Universidade do Porto, Portugal

c Gastroenterology department. Department of Pharmacology and Therapeutics. Centro Hospitalar de São João, Porto, Portugal

Corresponding author. Department of Pharmacology and Therapeutics. Faculty of Medicine, University of Porto. Alameda Prof. Hernâni Monteiro 420-319 Porto, Portugal.Tel.: +351 22 551 3600; fax: +351 22 551 3601.