Abstract 17202: Comparative Performance of the R2Chads2, Chads2, and Cha2Ds2-vasc Scores in Atrial Fibrillation
Background. Existing scores to estimate stroke risk in atrial fibrillation (AF) have shown variable performance. We compared the predictive performance of the R2CHADS2 score, which includes a term for renal dysfunction, to that of two existing stroke risk scores, CHADS2 and CHA2DS2-VASc.
Methods. We used data from the ORBIT-AF study, a national, prospective, outpatient registry of incident and prevalent AF in patients >18 years. We examined the association between impaired renal function (CrCl<60 mL/min) and 2-year risk of stroke/systemic embolism (SE) in separate Cox proportional hazards models with linear terms for CHADS2and CHA2DS2-VASc scores. We compared discrimination of the three scores using c-indices and evaluated calibration of R2CHADS2by comparing event rates in ORBIT to published rates from an external clinical trial population (ROCKET-AF) and an observational cohort (ATRIA).
Results. We included N=9743 patients enrolled at 174 ORBIT-AF sites. The median age was 75 years (IQR 67-82), 89.5% were white, 42.5% were female, and 76.4% were taking oral anticoagulation (OAC). Over a median follow-up of 2 years, N=214 stroke/systemic embolism (SE) events occurred (1.00 per 100 pt.-years). Impaired renal function was present in 35.4% of patients and was associated (HR; 95% CI) with increased stroke/SE risk in unadjusted models (1.65; 1.27-2.14). This association was attenuated in models adjusting for CHADS2 (1.21; 0.92, 1.60) or CHA2DS2-VASc (1.05; 0.79, 1.40). Discrimination (c-index; 95% CI) was similar for R2CHADS2, CHADS2 and CHA2DS2-VASc; results were consistent by baseline OAC use (Table). Stroke/SE event rates in ORBIT were lower than those in two external populations for all levels of R2CHADS2.
Conclusion: In a well-treated community patient population, renal dysfunction did not improve discrimination of traditional embolic risk models. Future studies examining the association between renal dysfunction and outcomes by type of OAC are needed.
Author Disclosures: E.C. O'Brien: Research Grant; Modest; BMS and Janssen. Consultant/Advisory Board; Modest; Portola. D.N. Simon: None. L. Thomas: None. G.C. Fonarow: Consultant/Advisory Board; Modest; Medtronic, Amgen, Johnson & Johnson, Bayer, Boston Scientific. Research Grant; Significant; NIH. Consultant/Advisory Board; Significant; Novartis. P.R. Kowey: Consultant/Advisory Board; Modest; Boehringer Ingelheim, Bristol Myers Squibb, Johnson & Johnson, Portola, Merck, Sanofi, Daiichi Sankyo. K.W. Mahaffey: Research Grant; Modest; AstraZeneca, Amgen, Bayer, Boehringer-Ingleheim, Bristol-Myers-Squibb, Daiichi Sankyo, Eli Lilly, GlaxoSmithKline, Johnson & Johnson, Merck, Novartis, Portola, POZEN Pharmaceutical, Schering-Plough, and The Medicines Company. Consultant/Advisory Board; Modest; Amgen, AstraZeneca, Glaxo SmithKline, Johnson & Johnson, and Merck. J.P. Piccini: Research Grant; Modest; Boston Scientific Corporation and Janssen. Consultant/Advisory Board; Modest; Forest Laboratories, Janssen, and Medtronic. E.D. Peterson: Research Grant; Modest; Eli Lilly & Company and Janssen.
- © 2015 by American Heart Association, Inc.