Hospital Admission Rates in Patients with COPD Throughout the COVID-19 Pandemic.

Purpose: Several studies report decreased hospital admissions for acute exacerbations of COPD (AECOPD) during the COVID-19 pandemic. However, there are no studies that compare AECOPD admissions with admissions for respiratory infections, including COVID-19. This study aimed to examine hospital admission rates for AECOPD, pneumonia, influenza, and COVID-19 among COPD patients, before and during the COVID-19 pandemic. Patients and Methods: We obtained anonymized data on hospital admissions of patients with COPD and a primary diagnosis code for AECOPD, pneumonia, influenza, or COVID-19, from the hospital patient admission register at a large Swedish hospital. The study compared the pandemic period (February 2020-March 2022) to a period before the pandemic (June 2017-January 2020). Sequential phases of the pandemic were evaluated separately. Monthly admission rates were compared using Poisson regression, controlling for admission month. Results: Comparing monthly admission rates during the pandemic with the prepandemic period, incidence rate ratios were 0.72 for AECOPD (95% CI 0.67-0.77; p<0.001), 0.56 for pneumonia (95% CI 0.49-0.62; p<0.001), 0.18 for influenza during the winter period (95% CI 0.10-0.30; p<0.001) and 0.79 for total COPD admissions, including COVID-19 (95% CI 0.75-0.84; p<0.001). The study showed significantly lower rate ratios for AECOPD, pneumonia, and total COPD admissions during the first, second, third, and fifth (Omicron) waves. No significant effect on admissions was seen after the withdrawal of restriction measures. Conclusion: There was a significant reduction in the overall rate of hospital admissions among COPD patients for AECOPD, pneumonia, and respiratory viral infections during the pandemic despite the rise in COVID-19 admissions. However, prepandemic admission levels returned in the post-restriction period.