Incremental prognostic value of renal function for stroke prediction in atrial fibrillation.

BACKGROUND: Renal function has been associated with an increased stroke risk in patients with atrial fibrillation (AF). However, whether renal function incrementally adds to risk prediction in both anticoagulated and non-anticoagulated patients with AF is unclear. METHODS: We used data from the Outcomes Registry for Better Informed Treatment of AF (ORBIT-AF)-a national, prospective, outpatient AF registry in patients aged >18 years (2010-2011). The association between baseline renal function and risk of stroke/systemic embolism (SSE) was evaluated in proportional hazards models adjusting for stroke risk score components. We compared discrimination of 2-year outcomes using C-indices and evaluated calibration by comparing event rates in ORBIT-AF to published rates from an external clinical trial population (ROCKET AF) and an observational cohort (ATRIA). RESULTS: Among 9743 patients included in the analysis, the median age was 75 years (interquartile range [IQR] 67-82), 89.5% were white, 43% were female, and 76% were taking oral anticoagulation (OAC). Over a median follow-up of 2.3 years, 214 SSE events occurred (1.00 per 100 patient-years). Continuous creatinine clearance (CrCl) was not associated with SSE risk after adjusting for other clinical factors (components of CHADS2 or CHA2DS2-VASc). Discrimination for predicting stroke (C-index; 95% CI) was similar for R2CHADS2 (0.65; 0.61-0.69), CHADS2 (0.65; 0.61-0.69), and CHA2DS2-VASc (0.66; 0.62-0.70). CONCLUSIONS AND RELEVANCE: In a community patient population with AF, renal dysfunction was not independently associated with embolic risk beyond other established risk factors in either OAC-treated or untreated patients. Additional study is needed to identify clinical factors that incrementally add to stroke risk prediction.

Duke Scholars

Author Emily O'Brien Population Health Sciences

Author Laine Elliott Thomas Biostatistics & Bioinformatics, Division of Biostatistics

Author Sean Pokorney Medicine, Cardiology

Author Michael J Pencina Biostatistics & Bioinformatics, Division of Biostatistics

Author Jonathan Paul Piccini Sr. Medicine, Cardiology