Ischemic Stroke Temporally Associated With AFib Tied to Increased Mortality Risk

Many patients with new-onset atrial fibrillation (AFib) experience their first ischemic stroke at the same time of their AFib diagnosis, according to study findings published in the journal Stroke.

Although the risk for ischemic stroke related to AFib is well-studied, the temporal relationship and mechanism is not well understood. Researchers conducted a population-based retrospective study to evaluate this relationship among patients with ischemic stroke temporally associated with AFib (ISTAF). 

The researchers collected from the Finnish AntiCoagulation in Atrial Fibrillation (FinACAF; ClinicalTrials.gov Identifier: NCT04645537) study, a retrospective cohort study including all adult patients with AFib in Finland between 2004 and 2018. A diagnosis of AFib was made per the International Classification of Diseases, Tenth Revision (ICD-10) codes.

The researchers included patients with new-onset AFib diagnosed between 2007 and 2018. Patients were followed up to 90 days from new-onset AFib diagnosis.   

A total of 229,565 patients (average age, 72.7; 50% women) with new-onset AFib were included in the study. Of these participants, 204,774 (89.2%) did not have an ischemic stroke, 12,209 (5.3%) had a previous ischemic stroke, and 12,582 (5.5%) patients had ISTAF. 

Of the patients with ISTAF, 2498 (19.9%) had strokes within 1 to 30 days before AFib and 10,084 (80.1%) in 0 to 30 days after AFib. From 2007 to 2018, the annual proportion of ISTAF decreased from 6.0% to 4.8% among patients with new-onset AFib. 

Compared to patients with AFib and no ischemic stroke, patients with ISTAF were more likely to be older, women, and have less education. Other factors associated with ISTAF were dyslipidemia, hypertension, prior bleeding, and dementia when compared to patients with AFib and no ischemic stroke. On the other hand, heart failure, renal failure, liver dysfunction, alcohol abuse, cancer, psychiatric disorders, and direct oral anticoagulant (DOAC) use was less likely among patients with ISTAF. 

Compared to patients with and without past ischemic stroke, patients with ISTAF had approximately a 1.5-fold (adjusted hazard ratio [aHR], 1.47; 95% CI, 1.39-1.57) and a 3-fold increased risk for death (aHR, 2.90; 95% CI, 2.76-3.04), respectively. 

The average CHA₂DS₂-VASc score was higher among patients with ISTAF compared to those with no ischemic stroke (3.4 vs 3.0; P <.001). Patients with past ischemic stroke had a higher CHA₂DS₂-VASc score than patients with ISTAF (6.0; P <.001).

From 2007 to 2018, the 90-day survival probability among patients with ISTAF increased from 0.79 (95% CI, 0.76-0.81) to 0.89 (95% CI, 0.87-0.91).

“[T]he reduction of patients with ISTAF and improvement in their survival rate over time appears a positive signal, for which underlying reasons warrant further research,” the researchers concluded. 

Study limitations included the inability to analyze AFib subtype and specific stroke details, the dates of diagnoses not necessarily reflecting onset date, changes in diagnostics and treatments over time, and a majority White patient population. 

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.