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Dialysis Discussion => Dialysis: News Articles => Topic started by: okarol on January 14, 2011, 10:19:28 PM

Title: Afib Common in Dialysis Population
Post by: okarol on January 14, 2011, 10:19:28 PM
Afib Common in Dialysis Population
   
By Todd Neale, Staff Writer, MedPage Today
January 14, 2011
   
MedPage Today Action Points
Explain that atrial fibrillation is highly prevalent in patients on hemodialysis (almost 8% annually).

Note that atrial fibrillation was also associated with an elevated one-year mortality rate of 39% in patients with atrial fibrillation (19% in patients who did not have the condition).
 
Review
Atrial fibrillation is highly prevalent and associated with an elevated mortality risk in patients on hemodialysis, researchers found.

From 1992 to 2006, the overall prevalence of atrial fibrillation in this population was 7.7%, increasing from 3.5% to 10.7%, Wolfgang Winkelmayer, MD, ScD, of Stanford University in California, and colleagues reported online in the Journal of the American Society of Nephrology.

The one-year mortality rate was 39% in patients with atrial fibrillation and 19% in patients who did not have the condition, which remained consistent throughout the study.
In absolute terms, the number of patients on hemodialysis increased from 103,833 to 223,466 during the study period.

"Given the ever-increasing number of patients with end-stage renal disease in the U.S. and elsewhere, greater attention should be paid to identifying potentially modifiable risk factors for atrial fibrillation that may be specific to patients undergoing maintenance hemodialysis," the researchers wrote.

Winkelmayer and his colleagues analyzed claims data from the U.S. Renal Data System to assess the prevalence of atrial fibrillation in the end-stage renal disease population. Medicare was the primary payer for all patients.

The increase in prevalence during the study occurred for permanent, persistent, and recurrent paroxysmal atrial fibrillation and affected all age groups.

After adjustment for demographics, Medicaid coverage, dialysis vintage, and comorbidities, prevalence increased by a relative 70% during the 15-year study period (RR 1.70, 95% CI 1.64 to 1.75).

As might be expected, the risk of atrial fibrillation increased with age -- a trend that parallels that observed in persons free of renal disease. Compared with patients younger than 45, those 85 and older had a more than six-fold increased risk atrial fibrillation (RR 6.67, 95% CI 6.42 to 6.97).

Women had 11% lower odds of atrial fibrillation (OR 0.89, 95% CI 0.88 to 0.90).

Most comorbid conditions were also tied to a greater risk of the abnormal heart rhythm, with the strongest association with heart failure (OR 2.46, 2.42 to 2.50).

Diabetes was, however, an exception as persons with diabetes were slightly less likely to develop atrial fibrillation (OR 0.98, 95% CI 0.97 to 0.99).

The finding "was surprising because fasting glucose is an established and important risk factor for atherosclerotic disease and has also been shown to be a risk factor of incident atrial fibrillation," the authors wrote.

"However, it is possible that patients with atrial fibrillation and coexisting diabetes experience disproportionately high mortality, which then removes these patients from the cohort and yields this counterintuitive inverse or lack of association (competing risks)."

The odds of atrial fibrillation also varied based on race. Compared with whites, the prevalence of the condition was 39% lower in blacks, 18% lower in Asians, and 47% lower in Native Americans.

The one-year mortality risk remained elevated in patients with atrial fibrillation throughout the study. After adjustment for demographics and other potential confounders, the risk was 45% higher (HR 1.45, 95% CI 1.44 to 1.46).

The authors noted that the study was limited by its reliance on medical claims data. As such, it is uncertain whether more aggressive coding practices could explain the increasing prevalence of atrial fibrillation.

The study was supported by a grant from the National Institute of Diabetes and Digestive and Kidney Diseases. Winkelmayer's recent support includes a Scientist Development Grant from the American Heart Association, a Norman S. Coplon Extramural Research Program Award from Satellite Healthcare, and an investigator-initiated grant from Fibrogen.

In the past two years, Winkelmayer has participated on advisory boards for AMAG Pharmaceuticals, Amgen, Astellas, Fresenius, GlaxoSmithKline, and Sandoz. One of his co-authors reported receiving research support from Amgen and Rockwell Medical, and serving on advisory boards for Amgen.

Primary source: Journal of the American Society of Nephrology
Source reference:
Winkelmayer W, et al "The increasing prevalence of atrial fibrillation among hemodialysis patients" J Am Soc Nephrol 2011; DOI: 10.1681/ASN.2010050459.
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