R(2(GFR))CHADS(2) and R(2(GFR))CHA(2)DS(2)VASc schemes improved the performance of CHADS(2) and CHA(2)DS(2)VASc scores in death risk stratification of Chinese older patients with atrial fibrillation

BACKGROUND: This analysis was carried out to refine the CHADS(2) and CHA(2)DS(2)VASc scores by combining creatinine clearance (CrCl) and glomerular filtration rate (GFR) and evaluate the performance of CrCl-based and GFR-based schemes in death risk stratification of Chinese older patients with atrial fibrillation (AF). METHODS: There were 219 older patients with AF, and all-cause mortality was assessed during the follow-up of 1.11 years. Renal function was evaluated using the CrCl formula and different GFR (Modification of Diet in Renal Disease [MDRD], Chinese MDRD [CMDRD], Mayo Clinic Quadratic [Mayo] and Chronic Kidney Disease Epidemiology Collaboration [CKD-EPI]) formulas, and five kinds of R(2)CHADS(2) and R(2)CHA(2)DS(2)VASc schemes were generated by combining CrCl and GFR with CHADS(2) and CHA(2)DS(2)VASc scores. RESULTS: In Cox regression multivariate analysis, CrCl <60 mL/min was moderately associated with death risk (P=0.122 and P=0.144). When MDRD, CMDRD, CKD-EPI and Mayo formulas were used to ascertain the GFR, GFR <60 mL/min/1.73 m(2) was significantly associated with death risk (P<0.001 for all). In the models with CHADS(2) and CHA(2)DS(2)VASc scores as the linear covariates, CrCl and GFR as the continuous variables were significantly associated with death risk (P<0.05 for all). C-statistics of CrCl-based schemes – R2(CrCl)CHADS(2) and R2(CrCl) CHA(2)DS(2)VASc – moderately exceeded that of CHADS(2) and CHA(2)DS(2)VASc scores (P=0.081 and 0.082). C-statistics of GFR-based schemes – R(2(GFR))CHADS(2) and R(2(GFR))CHA(2)DS(2)VASc – significantly exceeded that of CHADS(2) and CHA(2)DS(2)VASc scores (P<0.05 for all). CONCLUSION: Chinese older patients with AF with lower levels of GFR and GFR <60 mL/min/1.73 m(2) had a significantly high death risk, and those with lower levels of CrCl or CrCl <60 mL/min had a significantly or modestly high death risk. There was significantly better performance of GFR-based schemes and moderately better performance of CrCl-based schemes in death risk stratification compared with CHADS(2) and CHA(2)DS(2)VASc scores.