Stroke Not the Only Concern in Patients With A-fib

Patients with A-fib are at risk for a wide range of nonstroke conditions, with a stronger relationship seen for congestive heart failure than ischemic stroke, a meta-analysis shows.

The diversity of the outcomes linked to A-fib suggests that “there needs to be a focus on primary prevention,” lead author Ayodele Odutayo, MD (University of Oxford, England), told TCTMD. “And in this way we can make a lot more progress in improving outcomes for these patients.”

Although the development of non-vitamin K antagonist oral anticoagulants (NOACs) has clearly been beneficial, he said, those agents do not affect many of the outcomes shown to be disproportionately affecting patients with A-fib, Odutayo noted.

“So we need to find a way to improve their care and improve their quality of life, and the simplest way to approach that—and likely the most robust way—is through some renewed focus on primary prevention of these cardiovascular risk factors, or secondary prevention and control of these cardiovascular risk factors,” he said.

Strong Relationship With Heart Failure

For the meta-analysis, which was published online September 6, 2016, ahead of print in the BMJ, the investigators looked at data from 104 cohort studies with about 9.7 million participants, of whom 587,867 (6.1%) had A-fib.

They identified associations between A-fib and the following outcomes:

• Congestive heart failure (RR 4.99; 95% CI 3.04-8.22)
• Any stroke (RR 2.42; 95% CI 2.17-2.71)
• Ischemic stroke (RR 2.33; 95% CI 1.84-2.94)
• Cardiovascular mortality (RR 2.03; 95% CI 1.79-2.30)
• Major cardiovascular events (RR 1.96; 95% CI 1.53-2.51)
• Sudden cardiac death (RR 1.88; 95% CI 1.36-2.60)
• Chronic kidney disease (RR 1.64; 95% CI 1.41-1.91)
• Ischemic heart disease (RR 1.61; 95% CI 1.38-1.87)
• All-cause mortality (RR 1.46; 95% CI 1.39-1.53)
• Peripheral arterial disease (RR 1.31; 95% CI 1.19-1.45)

The only outcome evaluated that was not associated with A-fib was hemorrhagic stroke (RR 2.00; 95% CI 0.67-5.96).

Looking at absolute risk, the increase was greatest for congestive heart failure (11.1 events per 1,000 participant-years).

Those findings were mostly consistent across subgroups and in various sensitivity analyses.

Causality Unknown

To TCTMD, Odutayo said that the causality of the relationships is unclear and cannot be determined based on the results.

“Considering our observation that atrial fibrillation is also associated with an increased risk of heart failure, sudden cardiac death, and chronic kidney disease (in addition to ischemic heart disease), it seems likely that atrial fibrillation could be acting as a marker for shared underlying risk factors for cardiovascular disease,” his team writes in the paper. “These include hypertension, which is diagnosed in up to 90% of patients with atrial fibrillation, as well as obesity, diabetes, and obstructive sleep apnea.”

But despite the inability to establish causality, they argue, “there is merit in developing clinical risk prediction models for outcomes such as congestive heart failure; particularly given our relative and absolute risk estimates.”

Implications for Patient Care

Odutayo indicated that the findings highlight the need to broaden the scope of interventions aimed at improving outcomes in patients with A-fib.

One way to accomplish that is through implementing changes at the level of health systems to better track the care being delivered to patients, Odutayo said. Using electronic updates and alerts to provide feedback to clinicians and support decision-making has been shown to improve patient outcomes, he noted.

Alluding to the SPRINT trial results, Odutayo pointed out that patients at high cardiovascular risk may not be receiving aggressive enough treatment for hypertension, which represents another opportunity to intervene.

“Although a lot of studies do call for more primary prevention, in the case of [A-fib] and these common cardiovascular risk factors, there is actually renewed opportunity for that—ie, with more intensive treatment of hypertension and also more focus on system-level changes to improve care for these patients,” Odutayo said.

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