Atrial Fibrillation Common Among Patients With Atherothrombosis - Raises Risk Of Cardiovascular Death, Heart Attack And Stroke

Main Category: Cardiovascular / Cardiology
Also Included In: Blood / Hematology
Article Date: 10 Nov 2008 - 3:00 PDT

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Large, International REACH Registry Also Shows Many Patients With Atrial Fibrillation are Undertreated With Antiplatelet and Anticoagulant Therapies

A significant portion of patients with atherothrombosis also have atrial fibrillation (AF), greatly increasing their risk for cardiovascular death, heart attack and stroke, according to new findings from the large, international REACH registry published today in the American Heart Journal.(1) The findings also showed that standard treatments including anticoagulant and antiplatelet therapies are underused in AF patients.

The new findings from the REACH (REduction of Atherothrombosis for Continued Health) registry showed that AF was present in approximately 12% of patients who had atherothrombotic disease, which includes coronary artery disease (CAD), peripheral artery disease (PAD), and cerebrovascular disease (CVD). The findings also showed that, among patients with or at risk for atherothrombotic disease, the risk for death and non-fatal cardiovascular outcomes was greater for AF vs. non-AF patients, including more than twice as high for CV death (3.2% vs 1.4%; p<0.0001), 87% higher for death from all causes (4.3% vs. 2.3%, p<0.0001), 50% higher for non-fatal stroke (2.4% vs 1.6%, p<0.0001), and nearly 50% higher for the combined endpoint of CV death/heart attack/stroke and/or hospitalization for atherothrombotic events (17.9% vs 12.1%, p<0.0001). Despite these higher risks in AF patients, only a little more than half received anticoagulant therapy, only 60 percent received antiplatelet therapy, and less than one in five received both.

"We've known that AF is a major risk factor for ischemic stroke, but its prevalence and impact in the broader population of patients with atherothrombosis was previously unclear," said, lead author Shinya Goto, MD, PhD, FACC, Department of Medicine, Tokai University School of Medicine, Kanagawa, Japan. "Our findings help fill that gap, and show across all atherothrombotic disease categories, AF consistently increases the risk of death and non-fatal CV outcomes. For example, the combined endpoint of CV death, heart attack and stroke and/or hospitalization for atherothrombotic events was higher in AF patients no matter what form of atherothrombotic disease they initially had, and was highest in patients initially recruited with PAD. Further, our analysis underscores the need to determine the optimal management of AF patients with or at risk for atherothrombosis."

About the New REACH Analysis

The REACH registry is a large, contemporary, representative and geographically diverse cohort of stable outpatients with or at high risk of atherothrombosis.2,(3),(4) A total of 68,236 patients with either established atherothrombotic disease (CAD, PAD, or CVD, n=55,814) or at least three risk factors for atherothrombosis (n=12,422) were enrolled from 5,587 physician practices in 44 countries (in Europe, North and South America and Asia) in 2003-2004.

For this new analysis, the investigators identified REACH registry patients with or without AF, then compared those two groups in terms of risk factors, drug usage and one-year cardiovascular (CV) outcomes (CV death, heart attack and stroke).

AF status and one-year follow-up data were available for 63,589 patients. The prevalence of AF was 12.5%, 13.7%, 11.5%, and 6.2% among CAD, CVD, PAD, and risk factor-only patients, respectively; and 11.7% in patients with symptomatic atherothrombotic disease (CAD, CVD, or PAD together as one group). These prevalence rates are substantially higher than the estimated prevalence in the general population aged 40 years or more (2.3%) or 65 years or more (5.9%).(5)

Of the total 6,814 AF patients, 6.7% experienced CV death, non-fatal MI or non-fatal stroke within a year. Among the findings, the investigators showed that, after statistically adjusting for differences including age, sex, smoking, hypertension, diabetes, and hypercholesterolemia, the risks for death and non-fatal CV outcomes were worse in AF vs. non-AF patients:

- CV death 129% greater (3.2% vs 1.4%; p<0.0001)
- All-cause death 87% greater (4.3 vs 2.3, p<0.0001)
- Non-fatal stroke 50% greater (2.4% vs 1.6%, p<0.0001)
- The combined endpoint of CV death/heart attack/stroke and/or hospitalization for atherothrombotic event 48% greater (17.9% vs 12.1%, respectively; p<0.0001), and highest in patients initially recruited with PAD (27.1%)

Only 58.4% of AF patients received antiplatelet agents, and only 53.1% received anticoagulant therapy. The rate of bleeding requiring hospitalization was higher in AF vs non-AF patients, respectively: 1.5% vs 0.8% (p<0.0001); the investigators speculated that this may have been due to the more frequent use of anticoagulants (53.1% vs 7.1%).

References

1. Goto S, Bhatt DL, Rother J, Alberts M, Hill MD, Ikeda Y, et al. Prevalence, clinical profile, and cardiovascular outcomes of atrial fibrillation patients with atherothrombosis. Am Heart J 2008;156:855-863.

2. Bhatt DL, Steg PG, Ohman EM, Hirsch AT, Ikeda Y, Mas JL, et al. International prevalence, recognition, and treatment of cardiovascular risk factors in outpatients with atherothrombosis. JAMA 2006;295(2):180-189.

3. Ohman EM, Bhatt DL, Steg PG, Goto S, Hirsch AT, Liau CS, et al. The REduction of Atherothrombosis for Continued Health (REACH) Registry: an international, prospective, observational investigation in subjects at risk for atherothrombotic events-study design. Am Heart J 2006;151(4):786 e1-10.

4. Steg PG, Bhatt DL, Wilson PWF, D'Agostino R, Ohman EM, Rother J, et al. One-year cardiovascular event rates in outpatients with atherothrombosis. JAMA. 2007;297:1197-1206.

5. Feinberg WM, Blackshear JL, Laupacis A, Kronmal R, Hart RG. Prevalence, age distribution, and gender of patients with atrial fibrillation. Analysis and implications. Arch Intern Med 1995;155(5):469-73.

REACH REGISTRY

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