Background: In recent decades, the focus on preventing pneumonia in chronic obstructive pulmonary disease (COPD) has increased.

Aims and objectives: To identify the development over time in the proportion of patients with at least one moderate or severe pneumonia per year in patients with COPD on a national level.

Methods: A register-based serial cross-sectional study using Danish nationwide registers. On a yearly basis, we included all patients ?40 years of age with an ICD-10 diagnosis J44 from 1995 to 2018. We calculated the yearly proportion of patients with at least one moderate (redeemed prescriptions of relevant antibiotics) or severe pneumonia (relevant ICD-10 diagnosis codes from hospitalizations and ER visits).

Results: From 1995 to 2018, the yearly proportion of patients without pneumonia increased (27.5% vs 54.8%). The proportion of patients with at least one moderate pneumonia decreased (60.5% vs 46.2%). The proportion of patients with at least one severe pneumonia remained unchanged. The average number of moderate pneumonias/person/year decreased from 1.4 to 1.1. The average number of severe pneumonias was unchanged at 0.1.

Conclusions: In Denmark from 1995 to 2018, we have demonstrated a nationwide decrease in the average yearly number of moderate pneumonias in patients with COPD, and an increase in the proportion of patients without pneumonia.