Screening for Tuberculosis Before Anti-TNF Therapy
Author Information
Author(s): Ajit Lalvani, Kerry A. Millington
Primary Institution: Imperial College London
Hypothesis
The study investigates the effectiveness of T-cell interferon-gamma release assays (IGRAs) compared to the tuberculin skin test (TST) for diagnosing latent tuberculosis infection (LTBI) in patients with immune-mediated inflammatory diseases (IMID) prior to anti-TNF therapy.
Conclusion
IGRAs are more specific and probably more sensitive than TST for diagnosing LTBI in patients with IMID who are candidates for anti-TNF therapy.
Supporting Evidence
- IGRAs are more closely associated with risk factors for LTBI than TST.
- The proportion of TST-positive results is significantly lower in patients with IMID compared to healthy controls.
- Discordant TST-positive, IGRA-negative results are linked to prior BCG vaccination.
- Discordant TST-negative, IGRA-positive results are associated with steroid therapy.
Takeaway
Doctors need to check for tuberculosis in patients starting certain treatments because those treatments can make tuberculosis more dangerous. New blood tests are better at finding tuberculosis than the old skin test.
Methodology
The study reviews the performance of IGRAs in diagnosing LTBI in patients with IMID, comparing results with TST and assessing associations with risk factors for LTBI.
Potential Biases
Potential biases may arise from the small sample sizes and the reliance on existing studies with varying methodologies.
Limitations
The evidence base for IGRA performance in patients on anti-TNF therapy is limited and requires further longitudinal studies.
Participant Demographics
Participants included patients with immune-mediated inflammatory diseases such as rheumatoid arthritis, Crohn's disease, and psoriatic arthritis.
Statistical Information
P-Value
p<0.01
Confidence Interval
95% CI 5.14 to 110
Statistical Significance
p<0.05
Digital Object Identifier (DOI)
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