Abstract
This retrospective study included COPD patients who attended our medical center between January and October 2018, and analyzed the outcomes of their influenza vaccination, including medical visits, hospitalization, medical expenses, and the incidence of respiratory failure. Airflow limitation was stratified according to GOLD guidelines. Overall, 543 COPD patients were enrolled, including 197, 113, 126, and 107 mild, moderate, severe, and very severe patients, respectively. Of all the participants, 238 received an influenza vaccination (43.8%), which significantly reduced hospital utilization for moderate (odds ratio [OR] 0.22, 95%CI 0.09-0.51), severe (OR 0.19, 95%CI 0.08-0.44), and very severe patients (OR 0.15, 95%CI 0.05-0.5) compared to mild patients (OR 0.51, 95%CI 0.2-1.26); reduced emergency department utilization for moderate (OR 0.33, 95%CI 0.14-0.77), severe (OR 0.22, 95%CI 0.10-0.52), and very severe patients (OR 0.30, 95%CI 0.10-0.88) compared to mild patients (OR 0.64, 95%CI 0.30-1.37); and reduced the occurrence of respiratory failure for moderate (OR 0.20, 95%CI 0.06-0.68), severe (OR 0.40, 95%CI 0.16-0.98), and very severe patients (OR 0.36, 95%CI 0.15-0.82) compared to mild patients (OR 0% CI 0.14-3.20). Influenza vaccination is more effective in COPD patients with moderate, severe, and very severe airflow obstruction than in those with mild obstruction with respect to hospital utilization, emergency department utilization, and respiratory failure.