Asthma–Chronic Obstructive Pulmonary Diseases Overlap Syndrome Increases the Risk of Incident Tuberculosis: A National Cohort Study

PURPOSE: The association between asthma–chronic obstructive pulmonary diseases (COPD) overlap syndrome (ACOS) and tuberculosis (TB) has yet to be studied. METHODS: The newly diagnosed TB patients (age > 20 y) treated from January 2000 to December 2008 were included (ACOS cohort, n = 10 751; non-ACOS cohort, n = 42 966). The non-ACOS cohort involved patients with confirmed absence of ACOS. We calculated incidence rate ratios (IRRs) for TB in the ACOS and non-ACOS cohorts by using poisson regression analysis. Cox proportional hazards regression models were used to determine the adjusted HR (aHR) for TB in the ACOS cohort compared with the non-ACOS cohort. RESULTS: The aHR for TB was 2.41 (95% confidence interval [CI], 2.19–2.66) in the ACOS cohort. The TB risk was significantly higher in the ACOS cohort than in the non-ACOS cohort when stratified by age, sex, comorbidities, and atopy. Within the ACOS cohort, the aHR was higher among patients receiving SABAs+SAMAs, LABAs+LAMAs, and ICSs (aHR [95% CI]: 3.06 [2.75–3.41], 3.68 [2.93–4.61], and 2.79 [1.25–6.22], respectively; all P < .05). Furthermore, patients with more than 15 outpatient visits and hospitalizations per year demonstrated the highest aHR (8.09; 95% CI, 6.85–9.56). CONCLUSIONS: ACOS cohort potentially develop incident TB, regardless of the age,sex, comorbidities and atopy; even without receiving the inhalers.This risk is higher, especially in the ACOS cohort have a high frequency of medical services or receiving the inhalers such as SABAs+SAMAs, LABAs+LAMAs and ICSs.