Rheumatoid Arthritis Raises Stroke Risk in Patients With Atrial Fibrillation

Rheumatoid arthritis (RA) is a risk factor for ischemic stroke in patients with atrial fibrillation (AF), according to study results published in the journal Rheumatology.

Previous research has shown that RA increases the risk for AF to approximately 1.4-fold and the risk for ischemic stroke also by approximately 1.4-fold; however, little is known about how RA affects risk for ischemic stroke in patients with AF.

Researchers conducted a registry-based retrospective cohort study to assess the effect of RA on ischemic stroke risk after an AF diagnosis, as well as the likelihood of this population to receive oral anticoagulant (OAC) treatment for stroke prevention.

Eligible study participants were adults with newly diagnosed AF — based on a hospital encounter or prescription, whichever came first — between 2010 and 2017. Patients were included in the RA group if they fulfilled criteria for RA before or at the same time as their first AF diagnosis. If patients were diagnosed with RA after diagnosis of AF, they were included in the non-RA group.

Primary study endpoint was ischemic stroke. Secondary endpoints were ischemic stroke subtypes, including cerebral infarction due to embolism of cerebral arteries and/or due to unspecified causes.

Risk for ischemic stroke was determined used the CHA₂DS₂-VASc score, which accounts for the presence of congestive heart failure (HF), hypertension, diabetes, and vascular disease.

A total of 161,629 patients had incident AF, of whom 2750 (1.7%) had RA. Median follow-up for the RA and non-RA groups was 2.5 and 3.0 years, respectively. Patients with vs without RA were more likely to be women, older, have congestive HF, atherosclerotic cardiovascular disease (CVD), hypertension, diabetes, and stroke or transient ischemic attack (TIA) before first AF diagnosis. In addition, the RA vs non-RA group had higher mean CHA₂DS₂-VASc scores (3.40 vs 2.76).

In the study period, 121 (4.4%) patients with RA and AF had an ischemic stroke compared with 5463 (3.4%) patients without RA with AF. The most common subtype of stroke was cerebral infarction due to unspecified causes. Results also showed a high rate of mortality in the RA vs non-RA group (29.2% vs 21.5%).

During the 1-year follow-up, cumulative incidence of ischemic stroke for the RA and non-RA groups was 1.8% and 1.4%, respectively. In the 3-year follow-up, the rates were 5.0% and 3.3%, respectively. In the 5-year follow-up, the rates were 7.3% and 5.0%, respectively.

After stratifying by sex, incidence of ischemic stroke was higher among men with vs without RA, with 1-, 3- and 5-year incidence rates of 2.0% vs 1.3%, 5.4% vs 3.1%, and 7.6% vs 4.7%, respectively. However, cumulative incidence of ischemic stroke was mostly similar between women with and without RA.

After adjusting for age and sex, patients with vs without RA with AF had an increased risk for stroke (hazard ratio [HR], 1.25; 95% CI, 1.05-1.50). The effect size remained consistent even after the inclusion of comorbidities and OAC treatment to the model.

The researchers also noted that patients with vs without RA were less likely to receive OAC treatment (adjusted odds ratio [aOR], 0.88; 95% CI, 0.80-0.97).

Limitations of the analysis included potentially missing out on identifying some cases of AF; lack of information on lifestyle habits and risk factors for bleeding, which may have affected stroke risk; and the possibility of surveillance bias. 

The researchers noted that their findings emphasized “the need to improve stroke prevention in AF patients with RA.” They concluded, “Future studies are warranted to explore the effect of implementation of RA as a factor in CHA₂DS₂-VASc score, and whether increasing OAC coverage among AF patients with RA would aid in preventing [ischemic] strokes.”

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