Influenza vaccination and risk of respiratory failure in patients with chronic obstructive pulmonary disease: A nationwide population-based case-cohort study

Background: Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease which causes a considerable disease burden. Patients with COPD are at a higher risk for influenza infection and influenza vaccination are recommended at this high risk patient group. In the current study, we aimed to evaluate the association between influenza vaccination and the risk of respiratory failure (RF) in COPD patients. Methods: From 2001 to 2005, patients with newly diagnosed COPD were identified from the NHIRD, and were followed until 2010. We explored the influenza vaccination rate among this COPD cohort. Furthermore, patients who experienced RF were defined as case group, whereas the others were defined as control group. Baseline characteristic were compared and association between influenza vaccination and RF were evaluated. Results: The rate of influenza vaccination was significantly higher in patients age ≥65 years than those age <65 years (54.8% vs. 4%, p < 0.001). The vaccine cohort had more comorbidities, more health care utilization and more frequent acute exacerbations as compared with nonvaccine cohort. In multivariable logistic regression, influenza vaccination was associated with a reduced risk of respiratory failure (adjusted odds ratio [aOR] 0.87, 95% confidence interval [CI] 0.79–0.96). In subgroup analysis, we found that the association was insignificant in patients age