Background: This analysis was carried out to refine the CHADS₂ and CHA₂DS₂VASc 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 R₂CHADS₂ and R₂CHA₂DS₂VASc schemes were generated by combining CrCl and GFR with CHADS₂ and CHA₂DS₂VASc 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 m² was significantly associated with death risk (P <0.001 for all). In the models with CHADS₂ and CHA₂DS₂VASc 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 – R_2(CrCl)CHADS₂ and R_2(CrCl)CHA₂DS₂VASc – moderately exceeded that of CHADS₂ and CHA₂DS₂VASc scores (P =0.081 and 0.082). C-statistics of GFR-based schemes – R_2(GFR)CHADS₂ and R_2(GFR)CHA₂DS₂VASc – significantly exceeded that of CHADS₂ and CHA₂DS₂VASc scores (P <0.05 for all).
Conclusion: Chinese older patients with AF with lower levels of GFR and GFR <60 mL/min/1.73 m² 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 CHADS₂ and CHA₂DS₂VASc scores.
Keywords: atrial fibrillation, CHADS₂, CHA₂DS₂VASc, older patients, creatinine clearance, glomerular filtration rate