Fecal calprotectin (FC) is a highly sensitive disease activity biomarker in inflammatory bowel disease. However, there are conflicting reports on whether the diagnostic accuracy in Crohn’s disease is influenced by disease location. The aim of this study was to undertake a systematic review of the published literature. Relevant databases were searched from inception to November 8, 2016 for cohort and case control studies which had data on FC in patients with isolated small bowel (SB) and large bowel (LB) Crohn’s disease. Reference standards for disease activity were endoscopy, magnetic resonance imaging, computed tomography or a combination of these. The QUADAS-2 research tool was used to assess the risk of bias. There were 5,619 records identified at initial search. The 2,098 duplicates were removed and 3,521 records screened. Sixty-one full text articles were assessed for eligibility and 16 studies were included in the final review with sensitivities and specificities per disease location available from 8 studies. Sensitivities of FC at SB and LB locations ranged from 42.9% to 100% and 66.7% to 100% respectively while corresponding specificities were 50% to 100% and 28.6% to 100% respectively. The sensitivities and specificities of FC to accurately measure disease activity in Crohn’s disease at different disease locations are diverse and no firm conclusion can be made. Better studies need to be undertaken to categorically answer the effect of disease location on the diagnostic accuracy of FC.
General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Patients: 732 patients with IBD who were screened for LTBI using either TST or IGRA before starting a biological treatment.
Methods:Retrospective case note review of all IBD patients who were screened for LTBI prior to initiating biologics. Patients who developed active TB were identified from the London TB register.
Results:Of 732 IBD patients, 31 (4.2%) were diagnosed with and treated for LTBI with no significant side effects. Six of 596 patients (1.0%) who received biologic treatment developed active TB. There was a higher proportion of indeterminate IGRA in the immunosuppressive medication group compared to the non-immunosuppressive group (33% (59/181) compared to 9% (6/66), p<0.001).The combination of steroids and thiopurines had the highest proportion of indeterminate IGRA (64%, 16/25). High and low doses of steroids were equally likely to result in an indeterminate IGRA result (67% (8/12) and 57% (4/7), respectively).
Conclusions:This study highlights the challenges of LTBI screening prior to commencing biologic therapy, and demonstrates the risk of TB in patients who have been screened and who are receiving prolonged and continuing doses of anti-TNF.
SIGNIFICANCE OF THIS STUDYWhat is already known about this subject?Biologic treatment for IBD carries an increased risk of TB.Concomitant treatment with steroids can affect IGRA results.
What are the new findings?This is the first large retrospective study in the UK of the incidence of LTBI and active TB in IBD patients treated with biologics.We have identified the relationship between an indeterminate IGRA and immunosuppressive drugs used for IBD treatment.We have highlighted the importance of vigilance for active TB in patients treated with biologics.
How might it impact on clinical practice in the foreseeable future?This study may support new strategies in screening for LTBI in patients on immunosuppressive drugs for IBD. This study demonstrates the need for vigilance for the development of active TB in IBD patients on biologics, even if deemed of low epidemiological risk.
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