Abstract and Introduction
Abstract
Background: The Euro Heart Survey showed that antithrombotic treatment in patients with atrial fibrillation (AF) was moderately tailored to the 2001 American College of Cardiology, American Heart Association, and European Society of Cardiology (ACC/AHA/ESC) guidelines for the management of AF. What consequences does guideline-deviant antithrombotic treatment have in daily practice?
Methods: In the Euro Heart Survey on AF (2003-2004), an observational study on AF care in European cardiology practices, information was available on baseline stroke risk profile and antithrombotic drug treatment and on cardiovascular events during 1-year follow-up. Antithrombotic guideline adherence is assessed according to the 2001 ACC/AHA/ESC guidelines. Multivariable logistic regression was performed to assess the association of guideline deviance with adverse outcome.
Results: The effect of antithrombotic guideline deviance was analyzed exclusively in 3634 high-risk patients with AF because these composed the majority (89%) and because few cardiovascular events occurred in low-risk patients. Among high-risk patients, antithrombotic treatment was in agreement with the guidelines in 61% of patients, whereas 28% were undertreated and 11% overtreated. Compared to guideline adherence, undertreatment was associated with a higher chance of thromboembolism (odds ratio [OR], 1.97; 95% CI, 1.29-3.01; P = .004) and the combined end point of cardiovascular death, thromboembolism, or major bleeding (OR, 1.54; 95% CI, 1.14-2.10; P = .024). This increased risk was nonsignificant for the end point of stroke alone (OR, 1.42; 95% CI, 0.82-2.46; P = .170). Overtreatment was nonsignificantly associated with a higher risk for major bleeding (OR, 1.52; 95% CI, 0.76-3.02; P = .405).
Conclusions: Antithrombotic undertreatment of high-risk patients with AF was associated with a worse cardiovascular prognosis during 1 year, whereas overtreatment was not associated with a higher chance for major bleeding.
Introduction
Prevention of stroke and thromboembolism (TE) is the vanguard of atrial fibrillation (AF) management. When compared with both placebo and antiplatelet agents, oral anticoagulation (OAC) effectively prevents TEs in patients at high risk for such an event. In patients at low risk, an antiplatelet agent should suffice because the bleeding risk of OAC neutralizes the benefit of TE prevention in these patients. Based on this evidence and on expert opinion, the 2001 joint ACC/AHA/ESC guidelines on AF management provided recommendations for thromboprophylaxis in AF.
Despite the availability of trial evidence and guidelines, numerous observational studies have shown suboptimal application rates of OAC in clinical practice. The Euro Heart Survey recently reported that although the application rate of OAC has improved, antithrombotic drug therapy is only moderately tailored according to the risk classification scheme as proposed by the joint ACC/AHA/ESC guidelines. Several factors are thought to underlie this discordance between guidelines and practice.
Regardless of the rationale behind management decisions, it is important to know the consequences lack of guideline adherence may have. Stroke and bleeding rates in observational studies have been shown to compare quite well with event rates in OAC-treated, high-risk patients of randomized controlled trials, although these studies were based on small populations and some had methodological limitations. OAC efficacy in high-risk patients is just one aspect of guideline adherence in the whole spectrum of management of patients with AF, and the consequences of guideline deviance per se have not yet been addressed.
The aim of this report was to describe the consequences of guideline deviance in antithrombotic management from cardiology practices in a large European AF population. Our major questions were the following:
does undertreatment lead to an increased TE rate, and/or
does overtreatment cause avoidable bleedings?