Improving stroke risk prediction in atrial fibrillation with circulating biomarkers: the CHADS-VASc-Biomarkers model.

BACKGROUND

Anticoagulation reduces ischemic stroke in atrial fibrillation (AF) but increases bleeding. Existing risk calculators guiding anticoagulation decisions in AF have substantial limitations.

OBJECTIVES

To determine whether biomarkers of stroke risk for general populations are associated with stroke risk in AF and improve predictive performance of the CHADS-VASc (Congestive heart failure, Hypertension, Age >74, Diabetes, prior Stroke or transient ischemic attack or thromboembolism, Vascular disease, Age 65-74, Sex category) score.

METHODS

The REasons for Geographic And Racial Differences in Stroke (REGARDS) is a prospective cohort study of 30 239 adults enrolled in 2003 to 2007 and monitored for stroke. Participants with AF not taking anticoagulants and with no prior stroke history were studied. Nine circulating biomarkers were measured in stored baseline samples. Cox models, adjusted for demographics and stroke risk factors estimated associations of each biomarker with incident stroke. Then, models with CHADS-VASc score alone or adding biomarkers were compared using tests of fit (likelihood ratio test and Akaike information criterion) and risk discrimination (continuous net reclassification index, [NRI]).

RESULTS

Among 2411 participants with AF (median age 69 years, 55% female, 36% Black), 163 (7%) developed first-time ischemic stroke over 13 years. Higher N-terminal pro-B-type natriuretic peptide, growth differentiation factor 15, cystatin C, interleukin 6, and lipoprotein (a) were independently associated with higher stroke risk. Biomarkers substantially improved CHADS-VASc model fit (change in Akaike information criterion -13, P < .001) and predictive ability (5-year NRI 0.42). Adding only N-terminal pro-B-type natriuretic peptide and growth differentiation factor 15 yielded the best model fit and a similar NRI compared with all biomarkers.

CONCLUSIONS

Five biomarkers were associated with stroke risk in AF, and 2 of these improved CHADS-VASc performance. This improved CHADS-VASc-Biomarkers score can allow better selection of patients for anticoagulation to reduce stroke in AF.