Study Shows Renal Impairment Has No Risk Predictive Value in AFib Patients

A study published on March 19 in the Journal of the American College of Cardiology that was designed to determine the risk of ischemic stroke and thromboembolism (IS/TE)-associated renal impairment in patients with non-valvular atrial fibrillation found that renal impairment was not an independent predictor of IS/TE risk at one year and did not have incremental predictive value over established risk-stratification scores.

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Researchers in the United Kingdom and France followed 5,912 patients with non-valvular atrial fibrillation and available serum creatinine data enrolled in the Loire Valley Atrial Fibrillation Project from the first record of atrial fibrillation in 2000 to the end of 2010.

Twenty-six percent of these patients (1,537) had renal impairment. Renal impairment was defined as a reported history of renal failure or a baseline serum creatinine level of >133 µmol/dL in men and >115 µmol/dL in women. The investigators calculated the estimated glomerular filtration rate (eGFR) for each patient and recorded outcomes regarding thromboembolism, stroke, bleeding and all-cause mortality for one year.

They also calculated established risk-stratification scores for each patient — CHADS2 and CHA2DS2-VASc — and used these scores to calculate the overall rates of IS/TE.

Patients with renal impairment were older, more likely to be male, less likely to have paroxysmal atrial fibrillation, more likely to have comorbidities, and were at higher risk of stroke/TE and bleeding than those without renal impairment. Patients with renal impairment had higher rates of stroke/TE than those without renal impairment at one year, and patients with an eGFR >30 ml/min/1.73 m2 had higher rates of stroke/TE than patients with an eGFR ranging from 30 to 59 ml/min/1.73 m2 at one year.

However, after the results were adjusted for CHADS2 risk factors, renal impairment was not found to be associated with a significant increase in the risk of IS/TE. In addition, when the factor of renal impairment was added to the CHADS2 and CHA2DS2-VASc scores, it did not independently add to the predictive value of these risk-stratification scores, the authors conclude.

Keywords: Thromboembolism, Great Britain, Stroke, Renal Insufficiency, France, Risk Factors, Glomerular Filtration Rate, Creatinine, United States

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