Introduction Inflammatory bowel disease (IBD) is frequently treated with tumour necrosis factor-alpha inhibitors (anti-TNF). This is associated with an increased risk for reactivation tuberculosis (TB) in those with latent tuberculosis infection (LTBI), which preventive therapy can reduce by 74%.¹The British Thoracic Society (BTS) guidelines include tables calculating the risk of developing TB and need for prophylaxis.²

Method We retrospectively reviewed clinic letters from 2010 to 2014 for IBD patients referred for anti-TNF screening at an East London hospital. Ethnicity, age, years in the UK, Tuberculin skin test (TST) result, interferon-gamma release assay (IGRA) result, and use of prophylaxis was recorded. Adjusted annual risk was calculated as per the BTS guidelines and patients labelled as “high risk” if prophylaxis was indicated. This was compared with the number that received prophylaxis after TB specialist assessment.

Results Out of the 116 patients identified, 91% were prescribed immunosuppressants (e.g., prednisolone, azathioprine, mercaptopurine). 37 patients were classified “high risk” as per the BTS guidelines; however following TB specialist assessment only 9 patients received prophylaxis. 14 of the 116 patients demonstrated positive TST and/or IGRA, although none of the patients receiving anti-TNF therapy developed reactivation TB. 100% of Black African and Indian ethnicity were classified “high risk”, although at least 78% of people in these groups were UK residents for over 10 years.

Conclusion The BTS guidelines did not accurately predict which patients would require preventive therapy in this cohort. Clinical assessment and immunological testing by a TB specialist reduced the number receiving preventive therapy, without increased rates of TB.

Disclosure of interest None Declared.

References

1. Carmona L, Gomez-Reino JJ, Rodriguez-Valverde V et al. Effectiveness of recommendations to prevent reactivation of latent tuberculosis infection in patients treated with tumour necrosis factor antagonists. Arthritis Rheum 2005;52:1766–72

2. British Thoracic Society Standards of Care Committee. BTS recommendations for assessing risk and for managing Mycobacterium tuberculosisinfection and disease in patients due to start anti-TNF-alpha treatment. Thorax 2005;60:800–805