Predicting the Risk of Ischemic Stroke among Patients with Rheumatoid Arthritis Using a Simplified RA-CHADSV Score Based on the CHA2DS2-VASc Score

Background and Objectives: The aim of this retrospective cohort study was to develop a new score (RA-CHADSV) (rheumatoid arthritis - congestive heart failure, hypertension, age >= 75 years, diabetes mellitus, stroke/transient ischemic attack/thromboembolism, and vascular disease), modified from the CHA(2)DS(2)-VASc score (congestive heart failure, hypertension, age >= 75 years (doubled), diabetes mellitus, stroke/transient ischemic attack (doubled), vascular disease, age 65-74 years, and female), in predicting the risk of ischemic stroke in rheumatoid arthritis (RA) patients without atrial fibrillation (AF). Materials and Methods: Using the Taiwan's National Health Insurance Research Database, 592 patients with RA diagnosed between 2000 and 2002 were identified and followed until first occurrence of ischemic stroke or the last available date in the database. Incidence rate ratios (IRR) of ischemic stroke for the CHA(2)DS(2)-VASc score were calculated using Poisson regression models. A new prediction score RA-CHADSV was developed using multiple logistic regression analysis with bootstrap validation. Results: The area under the receiver operating characteristic curve of the newly developed RA-CHADSV score and the CHA(2)DS(2)-VASc score were 0.73 (95% confidence interval (CI) 0.64-0.82) and 0.70 (95% CI 0.61-0.79), respectively. The RA-CHADSV score was significantly associated with a higher ischemic stroke incidence in the patients who scored >= 1 (adjusted IRR 7.39, p < 0.001). Conclusions: A simplified RA-CHADSV score, with comparable efficiency as the CHA(2)DS(2)-VASc score, but easier to use clinically was developed for predicting the risk of ischemic stroke among non-AF RA patients.