Risk of tuberculosis with anti-tumor necrosis factor-α therapy: substantially higher number of patients at risk in Asia

AIM To assess the potential risk of tuberculosis (TB) in patients treated with anti-tumor necrosis factor-alpha (TNF-α) agents in Asia. METHODS Absolute risk increase (ARI) of TB was estimated for three widely used anti-TNF-α therapies using published standardized incidence ratios (SIR) from the French Research Axed on Tolerance of bIOtherapies registry and incidence (absolute risk [AR]) of TB in Asia. Assuming an association of increased TB risk with anti-TNF-α therapy and country TB AR (incidence), the ARI of TB by country was calculated by multiplying the SIR of the anti-TNF-α therapy by the country's TB AR. The numbers needed to harm (NNH) for each anti-TNF-α agent and numbers needed to treat (NNT) to reduce one TB event using etanercept therapy instead of adalimumab or infliximab were also calculated for each country. RESULTS The ARI of TB with anti-TNF-α therapies in Asian countries is substantially higher than Western Europe and North America and the difference between etanercept versus the monoclonal antibodies becomes more evident. The NNH for Asian countries ranged from 8 to 163 for adalimumab, 126 to 2646 for etanercept and 12 to 256 for infliximab. The NNT to reduce one TB event using etanercept instead of adalimumab therapy ranged from 8 to 173, and using etanercept instead of infliximab therapy the NNT ranged from 13 to 283. CONCLUSION Higher numbers of patients are at risk of developing TB with anti-TNF-α therapy in Asia compared with Western Europe and North America. The relative lower risk of TB with etanercept may be particularly relevant for Asia, an endemic area for TB.