Cost-effectiveness of QuantiFERON testing before initiation of biological therapy in inflammatory bowel disease.
BACKGROUND
Anti-tumor necrosis factor α drugs are known to reactivate latent tuberculosis (TB). Current guidelines recommend screening for latent tuberculosis infection, with either tuberculin skin test (TST) or interferon gamma release assays such as QuantiFERON-TB Gold (QFT-G). Given the high rates of anergy to TST among immunosuppressed inflammatory bowel disease (IBD) patients, there is considerable interest in evaluating the superiority of interferon gamma release assays over TST in this patient population to diagnose latent tuberculosis infection. We compared the performance of TST and QFT-G for screening latent TB among immunosuppressed IBD patients based on prevalence, mortality risk from reactivation TB, and costs.


METHODS
A decision analytical model was constructed to compare 1-year outcomes and costs of using TST or interferon gamma release assay in an immunosuppressed IBD population.


RESULTS
Under the base case scenario, for every 1000 patients screened, the QFT-G strategy resulted in 0.53 deaths from reactivation TB compared with 1.92 deaths using TST. The QFT-G strategy results in 1.85 reactivation TB versus 6.7 reactivation TB using TST. The model was not sensitive to background prevalence of latent TB. The cost of QFT-G would have to be more than double for the TST strategy to become more cost effective. QFT-G also remains the cost-effective option unless the sensitivity of the TST improves by 400%.


CONCLUSIONS
Under a broad range of parameter values, the QFT-G strategy dominates the TST strategy in cost-effectiveness. Consideration should be given to QFT-G as the preferred method of identifying latent TB in all immunosuppressed IBD patients.
*Division of Digestive and Liver Diseases, Columbia University Medical Center, New York, New York; †Department of Infectious Diseases, Boston University School of Medicine, Boston, Massachusetts; and ‡Mailman School of Public Health, Columbia University, New York, New York.
Arun
A
Swaminath
Nahid
N
Bhadelia
Y Claire
YC
Wang
D000328:Adult; D003362:Cost-Benefit Analysis; D003424:Crohn Disease / Q000188:drug therapy / Q000191:economics*; D003663:Decision Trees; D006801:Humans; D059425:Interferon-gamma Release Tests / Q000191:economics*; D055985:Latent Tuberculosis / Q000175:diagnosis / Q000188:drug therapy / Q000191:economics*; D008403:Mass Screening / Q000191:economics*; D017059:Models, Econometric; D011379:Prognosis; D014374:Tuberculin Test / Q000191:economics*