Renal Impairment and Ischaemic Stroke Risk Assessment in Patients With Atrial Fibrillation: The Loire Valley Atrial Fibrillation Project
What is the risk of ischemic stroke/thromboembolism associated with renal impairment and its incremental predictive value over established risk stratification scores in patients with atrial fibrillation (AF)?
Patients diagnosed with nonvalvular AF between 2000 and 2010 and available estimated glomerular filtration rate (eGFR) data in a four-hospital institution between 2000 and 2010 were identified. The outcomes of interest were ischemic stroke and thromboembolism. The study population was stratified into three categories according to eGFR (in ml/min/1.73 m2) corresponding the stages of chronic kidney disease (CKD): ≥60, 30-59, and <30. The incremental predictive value of renal impairment over CHADS2 and CHA2DS2-VASc scores were assessed. The authors focused on 1-year outcomes in their analyses.
Of the cohort (n = 5,912), 1,537 (n = 26%) individuals had renal impairment. Patients with renal impairment had a higher rate of stroke and thromboembolism, with patients with an eGFR <30 ml/min/1.73 m2 having a higher rate than those patients with an eGFR of 30-59 ml/min/1.73 m2. After adjustment for CHADS2 risk factors, renal impairment did not significantly increase the risk for ischemic stroke or thromboembolism at 1 year (hazard ratio for eGFR, 1.09; 95% confidence interval, 0.84-1.41). There was no statistically significant improvement in either the CHADS2 or the CHA2DS2-VASc scoring systems, even when the analysis was restricted to patients with at least 1 year of follow-up.
Renal impairment was not an independent predictor of ischemic stroke or thromboembolism in patients with nonvalvular AF, and did not significantly improve the predictive ability of established risk stratification scores at 1 year.
Although the possibility of adding renal impairment to current risk prediction scores in AF has been proposed in the past, the current analysis would suggest that this is of limited value. Renal impairment does not appear to add to the predictive value of current scoring systems to predict stroke risk in AF, although it should not be overlooked in risk prediction tools for bleeding.
Keywords: Thromboembolism, Blood Coagulation, Stroke, Follow-Up Studies, Warfarin, Atrial Fibrillation, Glomerular Filtration Rate, Confidence Intervals, Risk Assessment, Renal Insufficiency, Chronic
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