Renal function and mortality in patients with atrial fibrillation

Aim The aim of this study is to examine the association of the presence of chronic kidney disease (CKD) and estimated glomerular filtration rate (eGFR) values with mortality in patients with atrial fibrillation. Methods This posthoc analysis of a randomized controlled trial consisted of hospitalized patients with atrial fibrillation who were followed up for a median of 2.7 years after discharge. Kaplan-Meier curves, multivariate Cox-regression and spline curves were utilized to assess the association of CKD, CKD stages 2-5 according to the KDOQI guidelines, and the continuum of eGFR values with the primary outcome of all-cause death, and the secondary outcome of cardiovascular mortality. Results Out of 1064 hospitalized patients with atrial fibrillation, 465 (43.7%) had comorbid CKD. The presence of CKD was associated with an increased risk for both all-cause and cardiovascular mortality following hospitalization [adjusted hazard ratio (aHR): 1.60; 95% confidence intervals (95% CIs): 1.25-2.05 and aHR: 1.74; 95% CI: 1.30-2.33, respectively]. The aHRs for all-cause mortality in CKD stages 2-5, as compared with CKD stage 1 were 2.18, 2.62, 4.20 and 3.38, respectively (all P < 0.05). In spline curve analyses, eGFR values lower than 50 ml/min/1.73 m(2) were independent predictors of higher all-cause and cardiovascular mortality. Conclusion In recently hospitalized patients with atrial fibrillation, the presence of CKD was independently associated with decreased survival, which was significant across CKD stages 2-5, as compared with CKD stage 1. Values of eGFR lower than 50 ml/min/1.73 m(2) were incrementally associated with worse prognosis.