Danish researchers have found in a new study that Pneumonia-related atrial fibrillation (Afib) should not be considered a transient and benign finding. Further patients could be left with recurrent Atrial fibrillation and an increased thromboembolic risk if they didn't start anticoagulants
New-onset atrial fibrillation (AF) is commonly reported in patients with severe infections. However, the absolute risk of thromboembolic events without anticoagulation remains unknown.

A study was conducted to investigate the thromboembolic risks associated with AF in patients with pneumonia, assess the risk of recurrent AF, and examine the association of initiation of anticoagulation therapy with new-onset AF.
This population-based cohort study used linked Danish nationwide registries. Participants included patients hospitalized with incident community-acquired pneumonia in Denmark from 1998 to 2018. Statistical analysis was performed from August 15, 2021, to March 12, 2022.
Results:
Among 274 196 patients hospitalized for community-acquired pneumonia, 6553 patients developed new-onset AF.
The 1-year risk of thromboembolism was 0.8% in patients without AF vs 2.1% in patients with new-onset AF without anticoagulation; this risk was 1.4% among patients with AF with intermediate stroke risk and 2.8% in patients with AF with high stroke risk.
Three-year risks were 3.5% among patients with intermediate stroke risk and 5.3% among patients with high stroke risk.
Among patients with new-onset AF, 32.9% had a new hospital contact with AF, and 14.0% initiated anticoagulation therapy during the 3 years after incident AF diagnosis.
At 3 years, the all-cause mortality rate was 25.7% in patients with pneumonia without AF vs 49.8% in patients with new-onset AF.
This cohort study found that new-onset AF after community-acquired pneumonia was associated with an increased risk of thromboembolism, which may warrant anticoagulation therapy. Approximately one-third of patients had a new hospital or outpatient clinic contact for AF during the 3-year follow-up, suggesting that AF triggered by acute infections is not a transient, self-terminating condition that reverses with a resolution of the infection.
Reference:
Thromboembolic Risk in Patients with Pneumonia and New-Onset Atrial Fibrillation Not Receiving Anticoagulation Therapy by Mette Søgaard, et al. published in the JAMA Network Open.
doi:10.1001/jamanetworkopen.2022.13945