Background

Despite the evolution of biologic agents, the use of traditional systemic immunosuppressants still account for considerable proportion of systemic anti-psoriasis therapy. The risk of tuberculosis among psoriasis patients receiving such convention immunosuppressants is not clearly understood.

Methods and Materials

We used the retrospectively-collected data from the Taiwan National Health Insurance Research Database to perform this prospective cohort study. We included 94,585 adult patients with newly diagnosed psoriasis between January 1, 2001 and December 31, 2013. We documented the exposure of systemic anti-psoriasis therapies. The outcome is incident mycobacterium tuberculosis infection.

Results

During a mean 6.8 years follow-up, 703 (0.74%) incident tuberculosis was diagnosed and treated. The crude incidence of tuberculosis was 1.11 (95% confidence interval [CI] 1.03–1.19) events per 1,000 person-years. The result demonstrated that MTX (Hazard ratio [HR] 2.16, 95% CI 1.47–3.16) and tacrolimus (HR 5.31, 95% CI 1.66–17.01) were significantly associated with increased risks of tuberculosis. Noticeably, azathioprine was a borderline significant risk factor of tacrolimus (HR 2.63, 95% 0.96–7.21, P = 0.059). The risk of receiving adalimumab was twofold (HR 2.07) though not significant due to only one TB event was detected. Steroid was also associated with a dose-dependent increase of tuberculosis risk (HR 1.09, 95% CI 1.09–1.12, for every 1 mg of prednisolone equivalent dose per day).

Conclusion

The study found that among systemic anti-psoriasis therapy, methotrexate, tacrolimus, azathioprine and steroid may be associated with an increased risk of tuberculosis.