Tuberculosis infection in primary Sjögren's syndrome: a nationwide population-based study

Primary Sjögren's syndrome (pSS) is a systemic autoimmune disease and may complicate with interstitial lung disease. The risk of Mycobacterium tuberculosis (TB) infection in patients with pSS has not been determined. This nationwide population-based study aimed to explore the incidence and risk factors of TB infection in patients with pSS. We identified 4,822 pSS patients from the Taiwan National Health Insurance database and compared the incidence rates of TB infection in these patients with 48,220 randomly selected age-, sex-, and comorbidity-matched subjects without pSS. The Cox proportional hazard model was used to identify risk factors for TB in patients with pSS. The risk of TB was higher in the pSS cohort than in the control cohort with an incidence rate ratio (IRR) of 1.58 (95% confidence interval [95% CI] 1.13-2.18, p = 0.006). The risk factors for TB in the pSS cohort were age ≥60 years (hazard ratio [HR] 3.22, 95% CI 1.78-5.84; p < 0.001), and corticosteroid usage, which had a dose-dependent effect in the pSS patients compared to the nonusers (daily prednisolone dose or equivalent less than 5 mg/day: HR 2.34; p = 0.020, 95% CI 1.14-4.78; 5 mg/day to less than 10 mg/day: HR 4.79, 95% CI 2.15-10.68; p < 0.001; 10 mg/day or more: HR 12.19, 95% CI 4.42-33.63; p < 0.001). Patients with pSS had a higher risk of pulmonary TB in Taiwan, which was related to age ≥60 years and corticosteroid usage.