Pre-existing atrial fibrillation and risk of arterial thromboembolism and death following pneumonia: a population-based cohort study.
OBJECTIVE
To examine the effect of pre-existing atrial fibrillation (AF) and associated therapy on the risk of arterial thromboembolism (ATE) and death following pneumonia.


METHODS
Population-based cohort study (1997-2012) of 88,315 patients with first-time hospitalisation with pneumonia in Northern Denmark.


RESULTS
Of the included patients (median age 73.4 years), 8880 (10.1%) had pre-existing AF. The risk of ATE within 30 days of admission was 5.2% in patients with AF and 3.6% in patients without AF. After adjustment for higher age and comorbidity, the adjusted HR (aHR) with AF was 1.06 (95% CI 0.96 to 1.18). Among patients with AF, reduced risk of ATE was observed in vitamin-K antagonist users compared with non-users (aHR 0.74 (95% CI 0.61 to 0.91)). Thirty-day mortality was 20.1% in patients with AF and 13.9% in patients without AF. Corresponding 1-year mortalities were 43.7% and 30.3%. The aHRs for 30-day and 1-year mortality with AF were 1.00 (95% CI 0.94 to 1.05) and 1.01 (95% CI 0.98 to 1.05). In patients with AF, reduced mortality risk was observed in users of vitamin-K antagonists (aHR 0.70 (95% CI 0.63 to 0.77)) and β-blockers (aHR 0.77 (95% CI 0.70 to 0.85). Increased mortality was found in digoxin users (aHR 1.16 (95% CI 1.06 to 1.28)).


CONCLUSIONS
Pre-existing AF is frequent in patients hospitalised with pneumonia and a marker of increased risk of ATE and death, explained by higher patient age and comorbidity. Prognosis is closely related to preadmission medical treatment for AF.
Department of Clinical Epidemiology, Institute of Clinical Medicine, Aarhus University Hospital, Aalborg, Denmark Department of Cardiology, Aalborg University Hospital, Aalborg, Denmark Department of Anaesthesia and Intensive Care Medicine, Aalborg University Hospital, Aalborg, Denmark Aalborg Atrial Fibrillation Study Group, Aalborg, Denmark.
Jacob
http://orcid.org/0000-0002-2709-4647
J
Gamst
Department of Clinical Epidemiology, Institute of Clinical Medicine, Aarhus University Hospital, Aalborg, Denmark.
Christian Fynbo
CF
Christiansen
Department of Anaesthesia and Intensive Care Medicine, Aalborg University Hospital, Aalborg, Denmark.
Bodil Steen
BS
Rasmussen
Department of Cardiology, Aalborg University Hospital, Aalborg, Denmark Aalborg Atrial Fibrillation Study Group, Aalborg, Denmark.
Lars Hvilsted
LH
Rasmussen
Department of Clinical Epidemiology, Institute of Clinical Medicine, Aarhus University Hospital, Aalborg, Denmark.
Reimar Wernich
RW
Thomsen
D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D000925:Anticoagulants / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000188:drug therapy / Q000453:epidemiology*; D015331:Cohort Studies; D015897:Comorbidity; D003643:Death; D003718:Denmark / Q000453:epidemiology; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D011014:Pneumonia / Q000453:epidemiology*; D012306:Risk; D012307:Risk Factors; D013923:Thromboembolism / Q000453:epidemiology*
D000889:Anti-Arrhythmia Agents; D000925:Anticoagulants; D005343:Fibrinolytic Agents
EPIDEMIOLOGY