Advanced chronic kidney disease in non-valvular atrial fibrillation: extending the utility of R(2)CHADS(2) to patients with advanced renal failure

BACKGROUND: The R(2)CHADS(2) is a new prediction rule for stroke risk in atrial fibrillation (AF) patients wherein R stands for renal risk. However, it was created from a cohort that excluded patients with advanced renal failure (defined as glomerular filtration rate of <30 mL/min). Our study extends the use of R(2)CHADS(2) to patients with advanced renal failure and aims to compare its predictive power against the currently used CHADS and CHA(2)DS(2)VaSc. METHODS: This retrospective cohort study analyzed the 1-year risk for stroke of the 524 patients with AF at Metropolitan Hospital Center. AUC and C statistics were calculated using three groups: (i) the entire cohort including patients with advanced renal failure, (ii) a cohort excluding patients with advanced renal failure and (iii) all patients with GFR < 30 mL/min only. RESULTS: R(2)CHADS(2), as a predictor for stroke risk, consistently performs better than CHADS2 and CHA2DS2VsC in groups 1 and 2. The C-statistic was highest in R2CHADS compared with CHADS or CHADSVASC in group 1 (0.718 versus 0.605 versus 0.602) and in group 2 (0.724 versus 0.584 versus 0.579). However, there was no statistically significant difference in group 3 (0.631 versus 0.629 versus 0.623). CONCLUSION: Our study supports the utility of R(2)CHADS(2) as a clinical prediction rule for stroke risk in patients with advanced renal failure.