Factors Affecting the Tuberculosis Risk in Patients Receiving Anti-Tumor Necrosis Factor-α Treatment

Background: Tumor necrosis factor (TNF)-α inhibitors are known to increase the risk of tuberculosis (TB). Objectives: To examine the factors associated with an increased risk of TB in patients receiving anti-TNF-α treatment (aTNF-α-T). Method: Of 3,094 patients who received aTNF-α-T between 2003 and 2013, a total of 1,964 subjects with a follow-up time longer than 6 months were identified and included in this retrospective analysis. Potential risk factors for the development of TB in patients receiving aTNF-α-T were evaluated. Results: Of the 1,964 patients, 1,009 (51%) were male and 955 (49%) were female, with a mean age of 39.7 ± 13.9 years. The primary conditions requiring aTNF-α-T included ankylosing spondylitis (n = 875), rheumatoid arthritis (n = 711), Behçet's disease (n = 83), and others (n = 295). Sixteen patients [8 (50%) males and 8 (50%) females; 5 (31.2%) with pulmonary TB and 11 (68.8%) with extrapulmonary TB] developed TB, with a corresponding TB incidence of 466/100,000. No significant associations were found between age, gender, smoking history, pack-years of smoking, isoniazid (INH) chemoprophylaxis, type of anti-TNF-α agent, use of other immunosuppressive drugs, and the risk of TB (p > 0.05). Multivariate logistic regression analysis showed a significantly higher risk of TB in patients diagnosed with Behçet's disease, and a significantly lower risk of TB in patients with a tuberculin skin test wheal ≥10 mm in diameter (p < 0.05). Conclusion: aTNF-α-T is associated with an increased risk of pulmonary or extrapulmonary TB, even when follow-up protocols and INH chemoprophylaxis are implemented, and TB often develops in the later stages of treatment. The risk of TB was higher in patients with Behçet's disease and lower in patients who had a strong tuberculin skin test reaction.