Risk of Herpes Zoster in Patients with Pulmonary Tuberculosis—A Population-Based Cohort Study

Background: Pulmonary tuberculosis (TB), a global health problem, is typically caused by the bacterium Mycobacterium tuberculosis. Herpes zoster (HZ) is caused by the reactivation of the varicella-zoster virus (VZV). The reactivation of VZV can be caused by stress. We investigated whether pulmonary TB increases the risk of HZ development. Methods: This study used data that sampled a population of 2 million people in 2000 from the National Health Insurance Research Database. This cohort study observed Taiwanese patients aged 20–100 years with pulmonary TB from 2000 to 2017 (tracked to 2018). Pulmonary TB was defined as having two or more outpatient diagnoses or at least one admission record. To address potential bias caused by confounding factors, the control cohort and pulmonary TB cohort were matched 1:1 by age, gender, index year, and comorbidities. Patients with HZ before the index date were excluded. Results: A total of 30,805 patients were in the pulmonary TB and control cohorts. The incidence rate of HZ in pulmonary TB and control cohorts were 12.00 and 9.66 per 1000 person-years, respectively. The risk of HZ in the pulmonary TB cohort (adjusted hazard ratios = 1.23; 95% confidence interval = 1.16–1.30) was significantly higher than that of in control cohort. Among patients without comorbidities, the patients with TB were 1.28-fold more likely to have HZ than those without TB. Conclusion: Patients with TB should be well treated to avoid the potential risk of HZ occurrence. Although we identified the association between pulmonary TB and HZ, further studies are needed to confirm the result.