Introduction
Hospital admissions are important contributors to the overall burden of COPD. Understanding the patterns and causes of hospital admissions can help to identify hints and targets for preventive interventions.

Aim
The current study aimed to determine the five-year all-cause hospital admission trajectories of patients with COPD following their first-ever exacerbation-related hospitalization.

Methods
Patients with COPD were identified from the Danish national registries. Patients experiencing their first-ever exacerbation-related hospitalization, defined as the index event, between 2000 and 2014 were included. All-cause hospital admissions were examined during a subsequent five-year follow-up period, and categorized using the International Classification of Diseases, 10th revision (ICD-10).

Results
In total, 82964 patients with COPD were included. The average age was 72 (SD 10) years and 48% was male. Comorbidities were present in 58%, and 65% of the patients collected inhalation medication ≤6 months prior to the index event. In total, 337066 all-cause hospital admissions were identified, resulting in a five-year admission rate of 82%. Most admissions were due to non-respiratory causes (59%), amongst which cardiac events were most common (19%).

Conclusion
Hospital admissions following a first exacerbation-related hospitalization are common, non-respiratory events constitute the majority of admissions. Besides the respiratory causes, treatment targeting the non-respiratory causes of hospital admission should be considered to effectively decrease the burden of hospitalization in COPD.