Impact of renal dysfunction on clinical outcome in patients with low risk of atrial fibrillation

Background: The impact of renal dysfunction has been investigated in patients with non-valvular atrial fibrillation (AF). The aim of this study was to assess its additive prognostic value in low thromboembolic risk AF patients with CHA2DS2-VASc score 0-1. Methods and Results: A total of 617 non-valvular AF patients were enrolled and baseline serum creatinine was measured. Estimated glomerular filtration rate and estimated clearance of creatinine were calculated using the Modification of Diet in Renal Disease equation and Cockcroft-Gault formula, respectively. The primary endpoint was cardiovascular death and systemic thromboembolic events, including acute ischemic stroke, transient ischemic attack, and peripheral artery embolism. Of these, 338 individuals had clinical CHA2DS2-VASc score 0-1. Among these individuals, 23 patients had impaired renal function. During the follow-up period of 53.6±32.1 months, the annual composite outcome rate in AF patients with CHA2DS2-VASc score 0-1 was 0.40%/year. As compared with patients with preserved renal function, the annual composite outcome rate was significantly higher in patients with impaired renal function (2.92%/year vs. 0.21%/year, P<0.001). Moreover, on multivariate Cox regression analysis, renal dysfunction was the only risk predictor in these low-risk patients. Conclusions: Impaired renal function has an additive prognostic value for thromboembolic events and cardiovascular mortality in low-risk AF patients with CHA2DS2-VASc score 0-1.