A clinical risk score helped predict the risk of ischemic stroke, thromboembolism and death in patients with heart failure, according to an analysis of three nationwide registries in Denmark. However, the researchers noted the predictive accuracy was modest.

The risk score, known as the CHA2DS2-VASc score, had previously been shown to predict ischemic stroke, thromboembolism and death in patients with atrial fibrillation.

Lead researcher Line Melgaard, MSc
, of Aalborg University in Denmark, and colleagues published their results online in JAMA on Aug. 30. The findings were simultaneously presented at the European Society of Cardiology Congress 2015 in London.

The researchers included patients who were at least 50 years old when they were discharged from Danish hospitals between Jan. 1, 2000, and Dec. 31, 2012, with a diagnosis of incident heart failure. They excluded patients who received a vitamin K antagonist within six months of their heart failure diagnosis, were diagnosed with cancer within five years of their heart failure diagnosis or previously had chronic obstructive pulmonary disease.

Of the 42,987 patients in the analysis, 21.9 percent had atrial fibrillation at baseline.

Among the patients who did not have atrial fibrillation, the risk of ischemic stroke was 3.1 percent, the risk of thromboembolism was 9.9 percent and the risk of death was 21.8 percent.

Patients with a higher CHA2DS2-VASc score had a higher risk of ischemic stroke, thromboembolism or death whether or not they had atrial fibrillation, although the researchers noted the predictive abilities were modest.

At the highest scores, patients with heart failure and no atrial fibrillation had a high risk for all three conditions. The researchers said there was a comparable increased risk in patients regardless of whether they had atrial fibrillation, which they said indicated a dose-response relationship.

The risk of ischemic stroke in patients without atrial fibrillation was approximately 1.5 percent per year or higher with CHA2DS2-VASc score of 2 or higher. The 5-year absolute ischemic stroke risk was 4 percent or higher.

The researchers cited a few study limitations, including that they could not determine if patients had heart failure with preserved or reduced ejection fraction and could not estimate the symptom severity or functional classification because they did not have access to patients’ echocardiograms. They also analyzed patients with incident heart failure, so the findings may not be generalizable to the entire heart failure population. In addition, the study included patients with several comorbidities predisposing for stroke events, so the event rates may be higher than in clinical trials.